According to this recent
Byron York article, that film footage may have been a reenactment:
"Kerry told reporter Charles Sennott the oft-repeated story of the February 1969 firefight in which Kerry attacked the Viet Cong who ambushed his Swift boat.
Kerry won the Silver Star, as well as a Purple Heart, for his efforts.
But the story wasn’t about the firefight itself. It was also Kerry’s reaction to it.
The future senator was so “focused on his future ambitions,” Sennott reported, that he bought a Super-8 movie camera, returned to the scene, and re-enacted the skirmish on film.
It was that film, transferred to videotape, that Kerry played for Sennott."
A few Nam vets I know find the commercial hilarious, and wondered why he was dressed up like a grunt and waltzing through the jungle, mugging for the camera with a goofy grin, and carying an M-16 like a purse..