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 December 1, 1964, who was first employed by another participating employer on December 8, 1942, to June 30, 1943, and was again employed by the same participating employer on January 2, 1945, to July 31, 1951, and by another participating employer on September 26, 1954, to February 28, 1959, and was employed by another participating employer from June, 1959 to October, 1960 and was again employed by another participating employer commencing September 5, 1960, to November 30, 1961, upon retirement shall be granted prior service credit for said service. The prior service benefit shall be computed by using a prior service annual salary of five thousand three hundred forty dollars ($5,340).