Any volunteer firefighter or full-time paid firefighter of the Whiteville Fire Department as shown by record on May 5, 1971, or any volunteer or full-time paid firefighter employed after ratification of this act shall be eligible for benefits from the Supplemental Retirement Fund, provided that no firefighter shall be eligible for benefits from the Supplemental Retirement Fund unless such person has qualified for benefits as stated in Section 6.4, 6.5 or 6.6.