An active member of the General Assembly having no service credits or creditable service in the Fund may establish service credit and creditable service for periods during which he held an elective office in a municipality but could not participate in the Fund because the municipality was not a participant in the Fund. Service credits and creditable service may be established by payment to the Fund of an amount equal to the contributions he would have made if he had participated, with interest to the date of payment, together with the applicable municipality credits with interest.