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 February 1, 1968, who was first employed by the same participating employer from January 2, 1953, through January, 1957, and who was again employed by the same participating employer from January 2, 1961, through July 1, 1966, shall upon retirement be entitled to receive prior service credit for such employment prior to July 1, 1966. The prior service benefit for such employee shall be computed by using a prior service annual salary of three thousand eight hundred thirty-seven dollars ($3,837).