Rob de la Rive Box Photos Question

Does anybody here have any idea how scarce or rare original photos from Rob Box are?

He used to shoot photos of the Ferrari's that he had for sale and send these around the world, some with his stamp on the back, some without.
Some have become quite famous such as the one of the SWB that he had for sale (can't remember the S/N from the top of my head).

He might have had dozens printed of each (or less) but many will have vanished with time.

Just curious how scarce they are nowadays.