Notwithstanding the fact that their business time may not be devoted exclusively to the services of the state, any member of the general assembly or any of the general officers of the state, may elect to participate in the benefits provided by chapters 8 — 10 of this title by filing an application with the board on or before December 31, 1948, or within six (6) months from the date upon which that person first qualifies for that office, whichever is later. Notwithstanding any other provision of chapters 8 — 10 of this title, upon becoming a member of the system that person shall be entitled to prior service credit covering service rendered prior to the date of becoming a member of the system for service rendered to the state as a state employee, a member of the general assembly, or as a general officer.