I'm sure someone mentioned that on 6music recently.
It makes you wonder how often this sort of thing occurs. I mean; lots of art was "lost" during WWII. Not all of it was destroyed. Yet no-one person is in a position to give a sound guess as to just how much was actually destroyed as opposed to declared destroyed or appropriated, archived and forgotten about.
This isn't a case of a lost archive however. It is why original art is valued highly. It's a surprisingly volatile commodity.