Audio problem: When Williams is checking out the tray of meat he points and says "hmm, No, I really don't think so." His words don't match up to his mouth.
Audio problem: You hear a clunking of metal when Hanh hits Williams, especially when Williams throws the side kick. Clunking of metal can only be heard when metals clash. Even when metal hits rock, a different sound is made. So when flesh or bone clashes with metal, this sound cannot be made.
Answer: Yes, he filmed all of his scenes before he died. He died on July 20, 1973 - only six days before the film debuted in Hong Kong, and only a month before the film's US debut.
TedStixon