Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4911, 74-4913 and 74-4917, to the contrary, an employee who was first employed by a participating employer on September 1, 1952, until August 28, 1953, who was again employed by another participating employer on April 1, 1959, until December 31, 1967, who became a member of the Kansas public employees retirement system on January 1, 1962, and who has contributions on deposit with the Kansas public employees retirement system, shall receive service credit for all service with participating employers and shall be granted a vested benefit effective December 31, 1967.