I recall about one board that if you moved a resistor, it reported a different "Machine ID". Maybe it was just an LC to a Performa but it might be something similar. The odds o finding that out is slim to none unless you find a hi-res image of the TAM board (I'm not volunteering). I don't know the hardware specifics of the prototype, but if the hardware is slightly different, it may not have reported as a TAM until closer to the finished product. It's a guess but is possible.