Could be Dolphy's flute after all - yikes! I wrote to one of the examiners for the Guernsey auction of 2005 about the flute and he just replied:
I have no connections to answer the question whether or not this e-bay auction is legit, but I can tell you with certainly that Dolphy's flute was not in the Guernsey's auction. That was Dolphy's Selmer alto sax. I looked in the 2005
Guernsey jazz catalogue, just to be sure, but anyway I would have remembered, since it was such a special privilege to examine every instrument that came into that auction."
Dolphy -> Dolphy's estate -> John Coltrane -> ? -> eBay
How did it get from Coltrane to eBay!?