Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4902, 74-4911 and 74-4913 to the contrary, an employee of a participating employer who was first employed April 15, 1963, and who was born March 20, 1902, and who is employed by the participating employer on the effective date of this act, shall be an eligible member of the Kansas public employees retirement system as of April 15, 1963, upon the payment of appropriate employer and employee contributions, and shall be entitled to receive full credit for employment with said participating employer from said date of first employment.