Subject to regulations of the President, retired ships’ officers and retired members of the crews of vessels of the National Oceanic and Atmospheric Administration shall be entitled to medical, surgical, and dental treatment and hospitalization by the Public Health Service if the ships’ officer or crew member, (1) was on active duty as a vessel employee of the National Oceanic and Atmospheric Administration on July 1, 1963, or on July 19, 1963, whichever is later, and his employment as a vessel employee was continuous from that date until retirement, or (2) was retired as a vessel employee of the National Oceanic and Atmospheric Administration on or before July 1, 1963, or on July 19, 1963, whichever is later.