I have a feeling he's referring to the "interlaced" IBM logo that was bog standard on everything.
That's what I'm thinking. Wasn't that logo on every Model M 1391401 made from, what 1987 to 1992?
The text of the ad, well, he calls it a "1984 label" IBM Model M Clicky Keyboard, when looking at his own picture of the label, 1984 is the copyright date and the keyboard date is 5/5/87.
Also states:
"I have not seen any with this type of label printing lately." Huh? So the rarity is based on what the seller has personally come across?
"Original Model M is regarded as the best keyboard ever made and this it! This keyboard is fully functional...it was not refurbed just cleaned." OK, one of the best keyboards ever, don't think many of us would argue that. The best? Probably debatable as it's not a lot of folks' cup of tea. I don't recall seeing before a seller stating a keyboard was cleaned and NOT refurbished as a selling point. I guess I get it, he's saying it was in such good shape it didn't need it, just seems strange.
"The keyboard is from 1984 comes with the heavy duty ps/2 cord. A keyboard made over 25 years ago will connect to most existing pcs out there today!" Again, per his own pictures it's from 1987 and it's a bit of a stretch these days to say it will connect to most existing PCs when most new computers come with no PS/2 connector and while a geekhacker can find a suitable adapter I bet many folks won't.
"Has rubber disks on the back" Uhhh, going to have to go look at mine, this isn't ringing a bell.
"It may have come with a portable computer and never saw much use!" Doubt it.
Having said all that, it might be worth it, at least to some but kinda seems like he's halfway making this stuff up.