Im thinking more on the lines of salvaged from a written off boat bought in a job lot and popped on ebay. He used his mobile to post the auction so wouldnt be surprised if a few more popped up in the next couple days. I dont think even the dumbest thief would be that stupid to try and sell an outboard he's just nicked on ebay with all the evidence still attached.
But then again theres some really daft people out there