Thank-you everyone for your interest!
Brian, and thank-you VERY much for your help guiding me along throughout the process. For you, the garage is always unlocked!
Terry, I figure that if I am not able to find out the vehicles service history, I should be able to narrow it down to a few units in the Toronto (disposal) area that would have used the GPMG as well as a radio, which was evidently installed due to the holes over the rear wheel well.
Robin, I am taking precautions to avoid catching "take-apart-itis". The only "issue" I have now is that a green bug bit me and now I'm interested in anything olive green, but that's the least of my worries!
David and James, your guess is better than mine!
Tim, Wow, I suppose in the future I will be needing a bigger garage!