This has been an unusual year for me (by that meaning 2014 and 2015) as I've seen more movies than I usually do, including this one.
I should have added this one here some time ago, but I'm embarrassed to admit that I don't know that much about this particular unit or series of events, other than that there was an American unit, at least, that was dedicated to trying to preserve European cultural works. We have the book, but I haven't read it yet. I'll come back and update this after I do. Most of what I know about this unit is from reading an article on this topic in The New Republic. I read that article some time ago, and don't recall the details of it really well other than that I think I recall that at least some of the details of the film depart from the actual history of the unit. At least some of the story depicted in the film almost certainly departs from the actual history and was added for dramatic and storyline effect.
For the meantime, what I'll do is restrict my comments to just the material details of the film and not try to post on any larger historical items. I will note, of course, as is well known that the Germans looted vast amounts of European art, quite a bit of which is still missing (apparently one major item noted in the film is actually strongly suspected of being in certain private hands, which has yet to return it but which there is anticipation that they will at some point). Some is lost to history, no doubt, for all time, having been destroyed at one point or another during the war.
That the Germans went to such extent to loot art is truly amazing. The removal of significant artifacts by invading armies isn't a wholly new thing, but to engage in it to this extent is in the modern world. This reflected the sick and debased nature of the Nazi regime, which viewed itself as the pinnacle of everything, and therefore entitled to own everything. In reaction, the U.S. did form a unit of specialist who attempted to preserve and track down works of art. Whether that unit had an international composition, I don't know.
I also don't know if the unit was generally made up of middle aged men, as depicted in this film, but the use of middle aged men for various roles during World War Two actually was fairly common, contrary to the opposing supposition that's quite common. So, whether accurate to this endeavor or not, it's accurate to the war.
In material details, the uniforms and equipment are largely correct. About the only departure I could see was the odd use of British sidearms, which would have been very unlikely. Troops being equipped, in this unit, with M1 Carbines is correct for their use. Use of a captured German Kübelwagen is shown, which wouldn't have been surprising for a unit of this type. Other Allied vehicles depicted are correct. Amazingly, Red Army vehicles depicted are also correct, a pretty surprising thing for an American movie and demonstrative of the increased effort we've seen in recent years to be accurate in material details.
All in all the movie is worth seeing in part because it's a "small story", which World War Two offers quite a few of, but which have generally not been touched by film makers in the context of World War Two for quite some time. They're worth doing, and when done well, as this film is, they add to our overall understanding of the war.