I just bought a 1992 IBM Model M p/n 1397661 (a rare 1391401 variant with one-piece keys)
here on eBay. The seller accepted my $45 offer on his (already quite reasonable) asking price of $55. He has a couple more for sale, so I'm guessing he'll take $45 (plus shipping) for them too.
Neither Wikipedia nor Deskthority had this p/n in their lists (I've since added it), and it's
rarely been mentioned here on GH. Seems like a good chance to add an obscure variant to your collection!
Now if you'll excuse me, I'm off to hand out cocaine-laced lollipops to schoolchildren... Okay, I'm kidding, but you have to admit it's a good metaphor. :?)