The keycaps are original dyesub PBT keycaps (thank you for the help photekq!), PT layout.
Here are some of the photos, the stabilizers are really rusty, but the keycaps and the case itself are really nice, just dirty.
The full album here: http://imgur.com/a/PPMkv
It was really nice to find a keyboard that I've easily used some 20 years ago.
I hope to upload more photos until the weekend.