That sounds like the only plausible explanation Charley. I figured GM of Canada must have gotten their records directly from the plants, but in this case, it must have come from either the 1st owner who was required to submit a copy of the window sticker, or perhaps it passed through a dealer in Canada who was required to submit the info. You know, it probably wouldn't hurt to test the system again by submitting a known US car through GM of Canada just to see what happens...
It would certainly be a ground-breaking revelation for the hobby if per chance the US plants turned their production info over to Canada for the "master file".....
Up until now, why would anyone with a known US car bother to contact GM of Canada for docs? Probably just wishful thinking huh????
Verne