The board may, without a vote of the electors, provide for the issuance of, and issue, general obligation bonds of the district or for an improvement district thereof if:
(a) The principal amount of such bonds do not exceed the then unissued balance of the principal amount of bonds authorized at an election held in the district, or in such improvement district, prior to May 9, 1967;
(b) The bonds are issued for the same purpose as that for which said unissued bonds were authorized; and
(c) The bonds are issued in accordance with the provisions of this article, except for the requirement of a bond election.
Bonds issued pursuant to this section may bear interest at a rate or rates not to exceed 8 percent per year, payable semiannually, except that interest for the first year may be payable at the end of that year. When bonds are issued pursuant to this section, unissued bonds as referred to in (a) and (b) above in a principal amount at least equal to the principal amount of bonds issued pursuant to this section, shall be canceled by order of the board and shall not be issued.