Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, a county register of deeds who first became a member of the Kansas public employees retirement system on October 1, 1968, who first took office in January, 1937, and who later served two (2) terms as probate judge commencing March 3, 1947, shall be granted prior service credit under said retirement system for service prior to January 1, 1962, with the participating employer which was his employer when he became a member. The prior service benefit shall be computed by using a prior service annual salary of three thousand dollars ($3,000).