Factual error: During the flashback explaining what happened to Su Lin she has an ugly bruise on her face less than a minute after being hit. Bruises usually take at least a few hours to develop like that.
Factual error: When Han is fighting Williams, Williams throws a side kick to Han. Then he lifts up his hand to block - supposedly a metal hand - but his hand does not move one bit. It is not possible, due to that kind of force, for a hand to not move. Even if a hand is metal, the elbow will pivot. As well as the fact that after the kick, you see Williams' face is in pain. This is not possible as he is wearing soled shoes and kicking side on.
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