Obviously any shots of a paintting being underwater would be a re-production, any scene before like before the ships comes into cherborge where cal says 'he wont amount to a thing' perhaps that was the real ones.

It would be silly to think cameron was going to destroy the REAL paintings, though why not just use re-productions through out would make more sence i think. It seems like a waste of time if you ask me, gettin the real ones in, you cant really tell a fake from a real one on camera.