Bought two model Ms (and my first buckling spring boards) Thursday evening. I took an old mothballed machine to test them, waiting a PS/2 to USB converter...
I don't have a suitable 5.5.mm driver right now: cleaned both keysets, cases and top barrel plate, no broken rivets judging by sound and uniform feel.
The one I'm currently typing on is an ISO white logo model 1391413 with the French Canadian layout, made in Mexico and dated June 5th 1989.
The other one is a bit of an oddity around here: a Greenock board, white logo model 1391402, France French AZERTY, dated December 12th 1990. My plan is to convert it to the French Canadian layout, which is partway done. As you can see it is also missing a few keycaps; might get fancy and ask if they have any of those NOS Industrial cases left over...
Regards,
Darkshado