Yes other than advisers to the Viet Marines. However in72 during the Easter Offensive a Marine air unit (F-7’s I think, was sent to the RVN and they had supporting units and a infantry security unit. When the NVA was about to enter Saigon in April ‘75 Marine infantry were sent to cover evacuation of US nationals . I think that was Operation Eagle Pull. Then Marines were used in the ferocious little war with the Khmer on Koh Tang Island. Basically it would be unlikely this guy was there. He isn't forthcoming with his bona fides which anyone who has real combat time will tell you directly when and where they were.
I think you mean A-7 Corsair, not F-7. PS I am a Vietnam era veteran too being in ROTC and commissioned in May 1974.