Thanks Dave, I would of liked to spend more time looking around in there too, but we where leaving, @Joseph yes a think that is a signal, we have a few more around too, I have a bunch more pictures of the museum to post too!
Joe From this pic right here this GE M-250R is the late 60s version....I haven't seen a silver one with the newer modern door design (a few designs such as the thumb latch, the door hidge lock design, the refractor holder design (which has cast tabs instead of separate screwed in tabs as I can see in the pic) I am not sure if it was silver..it looks more grey to me but maybe in Canada they continued the silver ones....usually silver are darker colored...
Or maybe it's a Canadian version with a slightly different design like how the Canadian Form 400 powerpacks were cast instead of stamped.