If the board provides that any bonds issued under this chapter shall be payable from the income and revenues of any project acquired before July 1, 1971, any such provision for the payment of said bonds from the income and revenues of any such project theretofore acquired shall be subject to, and in all respects in full conformity and compliance with, the rights of the holders of any bonds or obligations payable from the income and revenues of any such project theretofore issued by the board and then outstanding.
SDCL 13-51A-16