The election to purchase additional retirement time in Section 36-27-101 shall be restricted only to previous part time employment in the Legislature. The election to purchase additional retirement time shall be restricted to part time employees or present full time employees who were previously part time employees who are now presently employed by the Legislature. The eligible legislative employee shall purchase such time by paying the additional amount he would have contributed had he been allowed to do so when the service was rendered. The contributions made under Sections 36-27-101 and 36-27-103 and this section shall be made by June 1, 1990.