Any member of the state employees retirement system who as a former deputy sheriff served prior to 1952 as a court officer in the Supreme Court, the Superior Court or the Court of Common Pleas may elect to obtain credit under the state employees retirement system for the period of his service as such. Such election shall be made in writing to the Retirement Commission not later than January 1, 1968. Persons so electing shall, within sixty days after filing such election, pay to the State Employees Retirement Fund a sum equal to five per cent of their salaries for such service.