Oh my... I just checked imdb and he isn't listed in the complete cast listing, but he could be uncredited, especially if his part was cut. I cannot say it's him, but damned good eye to even see that it might be!
EDIT: Ahahaha, stupid me! So yeah, I searched for his Office character name instead of his real name. Yes indeed, Rainn Wilson was in Galaxy Quest, verified on imdb cast list.
EDIT: Ahahaha, stupid me! So yeah, I searched for his Office character name instead of his real name. Yes indeed, Rainn Wilson was in Galaxy Quest, verified on imdb cast list.