Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, an employee of a participating employer who was first employed on July 18, 1967, and became a member of the Kansas public employees retirement system on August 1, 1968, who was first employed by a participating employer periodically from September 6, 1937, until May 21, 1943, and was employed by another participating employer periodically from September, 1943 until May of 1947 and employed by another participating employer periodically from August, 1954 until May, 1957 and by another participating employer periodically from July 1, 1957, until May 27, 1959, shall upon retirement be entitled to prior service credit with all participating employers prior to January 1, 1962. The prior service benefit shall be computed by using a prior service annual salary of four thousand fifty dollars ($4,050).