Here's my theory on this and where it comes from:
First, these AT model F have been "found" because I asked the seller of the F122 if he had some AT model F with the number 6450200
A few days later he answered that he found some (but pricey). After trying to get them for a lower price, the seller finally just put them on ebay.
The thing is, the F122 that I received from him seems to be a refurbished keyboard in an amazing shape. It was all wrapped and there was not even dust. To me it looks like it was a refurbished keyboard what had been stored waiting to be used again when another would fail and that it never happened.
If my theory is true, probably the seller just had access to them by PN and could not or didn't want to unwrap one to take pictures. Anyway, I still bought one, probably overpriced, but I will be able to determine this when I will get it since if it's in the same shape as my F122 then it won't be overpriced in my opinion. the shipping for the F122 only took 2 days for me since it's close to where I live. So I will be glad to post pictures of it once I get it.
Edit: BTW, I can't test it yet since I lack the pro micro and a female DIN5, but I will as soon as I get these parts. Still, the used/refurbished state implies it is working as far as I know.