The clerk of said employer shall, within thirty (30) days after the effective date of the ordinance of the municipality to be passed as provided in Section 21-29-5, prepare a statement showing the length of service of employees, prior to effective date of said ordinance, then employed by the employer and the total salaries or wages paid each in cash or warrants during the four (4) years of employment by the employer next before said effective date of said ordinance. Such facts shall, subject to correction after each employee is given ten (10) days within which to check and prove to the board any error therein, be the basis for the board to approve the issuance of prior service certificates and records and to determine the sum each prior service employee electing to come within the retirement system shall deposit in the employees’ savings fund. The secretary of the board shall, upon approval of the board, issue to each employee a prior service certificate. The clerk of the employer shall have the duty of keeping all service records and all records on the various funds provided by this article. The clerk shall on or before July 1, 1987, forward all service records and funds to the Public Employees’ Retirement System.