A heads up about this topic, Merc readers: the movie seems to be based on the events during WWII that are covered in the excellent documentary, The Rape of Europa. The documentary spends a fair amount of time discussing the actual GI's who fought to stop the Nazi's from stealing works of art. Check it out, it's a really great watch, and it's an Instant view on Netflix:
http://www.rapeofeuropa.com/