Notwithstanding the provisions of Kan. Stat. Ann. § 74-4913, any employee of a participating employer with an entry date of January 1, 1962, who became a member of the Kansas public employees retirement system on August 1, 1970, was first employed by said participating employer from April 3, 1944, to February 18, 1948, and was reemployed from December 10, 1948, to January 13, 1949, and from October 13, 1952, to December 8, 1955, and again employed on July 7, 1969, shall upon retirement receive prior service credit for employment with said participating employer prior to entry date whether such employment was continuous or not. A prior service benefit shall be computed by using a prior service annual salary of two thousand six hundred forty dollars ($2,640).