Also - that IBM label looks too big, was it pulled off something else and stuck over it? If the keys were custom made - why make the grey keycaps but not the ones for space and Alt? Why not use Black keys? Why not use a black lock-light label? Also, the back label could have come off another keyboard, which seems especially likely given that any 82G that I have seen had a permanently attached cable.
I am convinced that this was someone's mod job that someone hacked together and somehow ended up in Brian's hands.