Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, if any employee of a participating employer became a member of the Kansas public employees retirement system on April 1, 1963, and was first employed by said participating employer from April 1, 1939, until February 1, 1941, was reemployed by said participating employer on January 10, 1949, until February 1, 1957, and was employed by another participating employer on August 1, 1937, through March 1939, and re-employed by said employer May 15, 1957, until November 30, 1961, he shall be granted prior service credit upon retirement for all service with said participating employers performed prior to January 1, 1962, whether continuous or not. The prior service benefit shall be computed by using a prior service annual salary of six thousand sixty dollars ($6,060).