From what I recall that scene was mostly adding/subtracting numbers -- which you can't do on a slide rule. So the slide rules were artistic license in the movie. This also leads into the fact that they did have plenty of computers that helped get to the moon, although slide rules were used for a lot of quick calculations and estimation by the engineers. And my favorite slide rule, the Pickett N-600, was carried on several moon missions as a backup calculation device. (Here's a picture of it on a Gemini mission: https://commons.wikimedia.org/wiki/File:Buzz_and_his_pipe.jp...)