Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, an employee who became a member of the Kansas public employees retirement system on June 1, 1973, and who was employed by another participating employer from November 12, 1947, to June 27, 1969, shall upon retirement be entitled to receive prior service credit for said employment prior to January 1, 1971. The prior service benefit shall be computed by using a prior service annual salary of four thousand five hundred fifty-eight dollars ($4,558).