Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4902, 74-4911 and 74-4913, to the contrary, an employee who was employed by a participating employer on February 1, 1979, and who was born February 2, 1918, shall be a member of the Kansas public employees retirement system as of the first day of the first payroll period chargeable to the fiscal year ending June 30, 1981. Upon the attainment of membership by the provisions of this act, such employee and such employee’s participating employer shall thereafter be governed by the provisions of the Kansas public employees retirement act. Such employee may purchase participating service credit for all service with such employer under Kan. Stat. Ann. § 74-4919a.