Aside from being super yellow and full of dust, the AT101 is in excellent condition. I do not see any key shine, but I expect if there is any, it will come out more clearly after I wash and de-yellow the caps.
For the moment, I have disassembled the F/PC and plan to compare spring/hammer assemblies and barrels when my F/AT stuff gets here. I am curious to try to get it working with the AT or USB port, if I can get it hacked into a sane layout.
If I can find a way to do it cheaply, I think an F/PC/XT to USB + ANSI-ish layout would be a pretty cool mod for these useless old things.
Barring that, I may try drilling the barrels out of a broken Model M, mounting the F/PC barrels to the drilled front plate, etching a capacitive matrix PCB for it, and trying to build something on stripboard to make the keys register with the M's controller. That'd be like, the most ultimate keyboard ever.