(a) The creditable service of a member shall include all established creditable prior service and service as a member of the General Assembly since he last became a contributing member of the system, in respect to which he makes contributions to the system. It shall also include, in the case of a member who became such on July 1, 1967, and remained a contributing member of the system continuously thereafter until his death or his retirement under the system or until he otherwise separates from service.
(b) Any member who has prior service as a member of the General Assembly rendered after July 1, 1967, for which creditable service under this retirement system has not been obtained shall receive creditable service for such prior service subject to the following conditions and requirements:
(1) The prior service as a member of the General Assembly must have been rendered while the member was a contributing member of either this retirement system or the Employees' Retirement System of Georgia;
(2) Employee contributions made by the member during the period of such prior service must not have been withdrawn by the member; and
(3) Creditable service obtained under this subsection shall be applicable only to the Georgia Legislative Retirement System and shall have no application whatsoever to the Employees' Retirement System of Georgia or to any rights retained under that retirement system pursuant to the provisions of subsection (d) of Code Section 47-6-42.