74-49a55. Same; basis for computation. Notwithstanding the provisions of K.S.A. 74-4913 to the contrary, an employee of a participating employer who became a member of the Kansas public employees retirement system on June 1, 1963, who was first employed by said participating employer July 11, 1938, to January 20, 1948, and who had been previously employed by another participating employer from August 6, 1934, through June 1, 1936, and by another participating employer from September 1, 1936, to July 8, 1938, shall be granted prior service credit for said service on the effective date of this act. The prior service benefit shall be computed by using a prior service annual salary of three thousand nine hundred eight dollars ($3,908).