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 January 1, 1967, who was first employed by said participating employer on January 12, 1953 until January 14, 1957, shall upon retirement be granted prior service credit for all service with a participating employer prior to January 1, 1967. The prior service benefit shall be computed by using a prior service annual salary of three thousand fifty-six dollars ($3,056.00).