Any provision of the Constitution to the contrary notwithstanding, any person who served as an officer of Mobile county or any municipality therein before the establishment of a pension or retirement system for the benefit of the elected or appointed officers of such county or municipalities shall be eligible to receive a pension or retirement benefit in all respects equal to officers serving when such pension or retirement system was established. The governing body of the county and of each municipality therein is hereby authorized to expend any funds not otherwise appropriated that may be required to pay the benefits payable to such former officers.