I'll look through my books, but I know on the first day Fischer arrived at the Stadium at 5:00 when the game was due to start, so he was a few minutes late due to traffic.
ETA: July 7, 1972 - 20 minutes late.
July 11, ditto - 7 minutes late.
July 16, ditto - 8 minutes late.
July 17, ditto - 15 minutes late
He was late for 20 out of 21 games in Reykjavik, but not seriously late.
I have not seen the movie yet... I am looking forward to watching the movie. Watching the trailers, one in particular I find a little unbelievable... I'm talking about this clip:
Look at the clock when Fischer finally arrives (his clock on the left):

Seems an hour has past... and what does he do, adjust the pieces. (Not sure why the other clock has advanced 50 seconds? Nobody has moved yet...) Does anyone recall Bobby Fischer being an hour late for a tournament match? I cannot even find record of this game taking place... maybe I need to look more.
I'm sure more questions will be asked once we all see the movie.