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, 1966, and who was previously employed by said employer from February 24, 1935 through December 31, 1942 and from March 30, 1943 through May 7, 1945, shall upon retirement be granted prior service credit for all service with said employer prior to January 1, 1962. The prior service benefit shall be computed by using a prior service annual salary of one thousand three hundred and seventy dollars ($1,370).