IMDb says “Ron Gilbert was an extra in Ewoks: The Battle Of Endor”.
Thimbleweed Park says he was an extra in Howard The Duck (presumably one of the crowd scenes with Lea Thompsons Band).
While I´d taken each of those on their own not really to be true (imdb inacurate and TwP to be just kidding) the combination of both leads me to believe that both might actually true.
So did you Lucasfilm Games guys do some minor extra work in movies, too?
What´s next David Fox at the Berlin book burning in Last Crusade?
Gary Winnick voicing a dinosaur in Land Before Time?