Okla. Stat. tit. 21, § 1626

The false making or forging of an evidence of debt purporting to have been issued by any corporation and bearing the pretended signature of any person as an agent or officer of such corporation, is forgery, a Class B3 felony offense, in the same degree as if such person was at the time an officer or agent of such corporation; notwithstanding such person may never have been an officer or agent of such corporation, or notwithstanding there never was any such person in existence.