Scott 343 from the 1960 wild animals overprinted series:
This was found in a recently bought lot. I suspect the top stamp overprint is just a perfect smudge of the normal at bottom. This is a CTO stamp with full gum and the cancel is definitely on top of the overprint. There are also specks of ink to the left of the giraffe's neck which I believe to be setoff/transfer, probably of the "cancel" printing.
This is probably an interesting but not valuable freak, but I was wondering if it might be another type overprint that I should be trying to track down? And does anyone have something similar to show?