Nothing in this article shall limit or otherwise restrict the power of the governing body of any municipality that has a retirement system under this article to adopt such vacation and sick leave policies for its employees as it deems necessary. Any such municipality having a vacation and sick leave policy that provides for the payment of unused accumulated annual leave, personal leave or both to employees at the time of their retirement shall be authorized to make such payments to any employee who retires or has retired after September 30, 1991.