Back in 2001, I co-wrote a movie for Roger Corman, RAPTOR, which was directed by Jim Wynorski, a delightful fellow who specialized in directing movies that utilized previously shot action footage.
In the case of RAPTOR, we used dinosaur footage from three CARNOSAUR movies that Corman had made previously. We even brought in a couple of actors who had been dinosaur food in those CARNOSAUR films to shoot additional scenes.
What can I tell you? A paycheck is a paycheck.
Interestingly, the score for RAPTOR is credited to Oscar-winner James Horner (TITANIC). I'm not sure what earlier Corman film that was taken from.
Also of interest: When I do an autograph show, I get a lot of people who ask me to sign their DVDs of RAPTOR.