Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, an employee of a participating employer who became a member of the Kansas public employees retirement system on May 1, 1967, and who was previously employed by another participating employer from January 1, 1937 until May 15, 1946 and from June 1, 1946 through December 15, 1951 by another participating employer, shall upon retirement be granted prior service credit for all service with all employers prior to January 1, 1962. The prior service benefit shall be computed by using a prior service annual salary of two thousand eight hundred and five dollars and eighty-five cents ($2,805.85).