I interpreted your comment about the box to mean it didn't look original. So it came with branded Kimber tupperware and all the added stuff like documentation, takedown tool, etc was there? If not, that further supports my theory. A wet or damp environment would ruin most of the stuff they include in the carry case. If all the factory accoutrements are there and in good shape, then this is a real head scratcher.
Hope you get this sorted. I can imagine your disappointment. I'd be interested in what the seller says.