I see no mention of APL in the auction.
The keyboard is a 60G' which was the retail PN of the 52G9658.
Indeed, for some reason when I googled the KB571 number the sites that come up at the top were related to APL keyboards - some discussing the fact that Unicomp sold APL keycaps that were easily put onto the two piece variety...
Since the seller had expressed that he had been looking forward to using it, I sensed a kindred spirit and actually sent him a note telling him he might wish to keep the thing himself. He has since pulled the auction, though it may have been just to retool the listing with some of the info I gave him. Though it was an opportunity for a potentially great price for a NIB model M, I could just imagine him trudging along in ignorance on a cheap modern pos and I didn't have the heart to let that happen...
I hope he does keep it. That would make me feel pretty good.