Either a 2.5" # 19 in nickel or a # 66.
I'm sure it was a model 66 w/2.5" barrel or a model 19 with nickel plating. It is one of my all time favorite revolvers, along with the 4" version of the same with a square butt. That was one hell of a movie, a little slow in the first few minutes, then it takes off.