¶1 The major issue on this appeal is whether the evidence that defendant knew the television sets were stolen at the time he received them was sufficient to go to the jury. If it was, defendant’s motion to dismiss was properly denied. Considering the evidence in the light most favorable to the State, as we are required to do, State v. Jones, 32 N.C. App. 408, 232 S.E. 2d 475, cert. denied and app. dism. 292 N.C. 643, 235 S.E. 2d 63 (1977), we find the following: In May or June 1977, defendant purchased from James Williams two color TVs and two stereos, still in their sealed boxes and stamped “Brown-Rogers-Dixson.” He paid $250 or $275 each for the TVs and $150 each for the stereos. Later he purchased another console color TV from Williams for $300. An additional TV and stereo were delivered to his business for purchase by Jimmy Britt. On 3 November 1977, defendant told the SBI that he knew the items purchased from Williams were stolen.
¶2 Defendant argues that this statement of 3 November is the only evidence that defendant knew the items were stolen, and that it is not probative because Bobby Davis had visited defendant on 15 September 1977 and told him that they were stolen. Defendant argues that the fact he knew on 3 November, having *421 been told by Davis on 15 September, does not mean he knew at the time he purchased the items.
¶3 The State presented further evidence, however. On 3 February 1978 defendant told the SBI that “before Labor Day 1977” he had told an FBI agent “that Britt had the stolen TV and stolen stereo.” Davis’ visit with defendant was after Labor Day. And while defendant is not charged with receiving the items allegedly purchased by Britt, they were acquired from Williams under circumstances identical to the two transactions for which he was charged. If defendant knew in the summer of 1977 that the items Britt purchased were stolen, there is a reasonable inference that he knew the ones he purchased were stolen as well. Further, defendant told the SBI on 3 February that when Andy Creech bought a TV and stereo from him on 15 June, Creech knew they were stolen. Defendant does not attempt to explain how Creech could have known this if defendant did not know.
¶4 Other evidence supports an inference of defendant’s knowledge. Defendant told the SBI that there was no question in his mind that Britt knew the sets were stolen, because of the good prices Britt got. Defendant got the same low prices on the items he purchased. Defendant purported to believe that the prices were low because the sets had been damaged and repaired, yet they arrived in sealed boxes. When defendant checked a serial number with the FBI and got no information that the set was stolen, he nevertheless told the agent that “if any of this stuff is stolen, it has got to be an inside job.”
¶5 Defendant argues that to withstand his motion the State is required to show that he had absolute knowledge that the sets were stolen. In defendant’s view, any reasonable grounds he had to believe that the items were stolen are insufficient, and he cannot be charged with knowledge until 15 September when he “knew for certain,” having been told by Davis that the sets were in fact stolen. G.S. 14-71, as amended in 1975, provides that a person shall be guilty of receiving stolen goods if he receives them “knowing or having reasonable grounds to believe” that they are stolen. Furthermore, guilty knowledge may be inferred from the circumstances. State v. Hart, 14 N.C. App. 120, 187 S.E. 2d 351, cert. denied, 281 N.C. 625, 190 S.E. 2d 469 (1972). In spite of defendant’s argument to the contrary, we find that sufficient *422 evidence was presented to take the case to the jury. There was no error in the denial of defendant’s motion.
¶6 Defendant next argues that he was denied his right to a speedy trial because he was not brought to trial within 120 days of his indictment. His reliance upon the Speedy Trial Act, O.S. 15A-701 et seq., is misplaced, however. The Act is Sec. 1 of Chapter 787 of the 1977 Session Laws, and Sec. 2 of that chapter says plainly: “This act shall apply to any person who is arrested . . . or is notified . . . that an indictment has been filed . . . against him, on or after October 1, 1978.” As defendant was indicted on 30 May and arrested on 31 May 1978, the Act is clearly inapplicable to his case. Accord, State v. McLawhorn, 43 N.C. App. 695, 260 S.E. 2d 138 (1979). Defendant concedes that he did not petition for a speedy trial, as was provided for by G.S. 15A-702 & -703 prior to the enactment of the Speedy Trial Act. We find no merit in this assignment of error.
¶7 No prejudicial error appears in the court’s allowing testimony that there were three thefts from Brown-Rogers-Dix-son. While it is true that defendant was charged with only two counts of receiving, defendant himself testified that James Williams made three deliveries to defendant’s place of business. And we fail to see how defendant would be prejudiced by evidence that a third party committed a theft in which defendant did not take part.
¶8 We agree with defendant that the court erred in allowing SBI Agent Shaw to give his opinion of the value of the TV sets, since no foundation had been laid for this opinion testimony. However, we do not find that this error was prejudicial. In fact, defendant has not argued any prejudice to his case by the admission of this testimony. Nor do we find prejudice in the admission of State’s Exhibits 11 and 12 for the purpose of illustrating testimony. Defendant argues that the “best evidence rule” was violated because the State could have produced the sets in question, but we note that the best evidence rule applies to writings introduced into evidence to prove their contents. 2 Stansbury’s N.C. Evidence § 190 (Brandis Rev. 1973).
¶9 On cross-examination, defendant was asked, “Mr. Allen, during the last six months, isn’t it a fact, that you have conspired with other people to break into the house of Reginald Shirley and *423 steal some guns?” Defendant’s objection to this question was overruled, and he assigns error to this ruling. He cites no authority for his position, arguing simply that the question was “unfair.” It is the law in North Carolina that for the purpose of impeachment a witness may be asked whether he has committed specific criminal acts. State v. Gainey, 280 N.C. 366, 185 S.E. 2d 874 (1972). The question was properly allowed.
¶10 On rebuttal, the State called William Taitón, and defendant objects to the admission of his testimony since Talton’s name was not on the list of potential witnesses for the State given to defendant before voir dire of the jury. Defendant raised this objection at trial, and the court inquired whether any of the jurors was acquainted with the witness. None responded that he was. Defendant now contends that he was prejudiced because Talton’s testimony conflicted with defendant’s on a particular point, and, not knowing that Taitón would be called, he was not prepared with witnesses who could corroborate defendant’s testimony on that point. Defendant did not object on this ground at trial, however, or ask for a recess in which to secure witnesses to counteract Talton’s testimony. We find no prejudicial error here.
¶11 Defendant assigns error to the court’s statement in the charge to the jury of the essential elements of receiving stolen goods, arguing not that the instructions given were incorrect, but that the court should have elaborated upon the “skeleton” charge that he gave. Defendant submitted no requested instructions to the trial court, however, and we find that the instructions given were sufficient. See State v. Boyd, 278 N.C. 682, 180 S.E. 2d 794 (1971).
¶12 Although defendant is correct that Willie Cooley, the Brown-Rogers-Dixson employee who was involved in the thefts, was not an accomplice to the crime of receiving stolen property, we find no prejudice to defendant from the court’s charge on this point, directed as it was to the fact that the jury should examine Cooley’s testimony with extreme care. The error could only have worked to defendant’s benefit. See State v. Saults, 294 N.C. 722, 242 S.E. 2d 801 (1978).
¶13 The defendant received a fair trial, free from prejudicial error.