Don't be too concerned about the Vin having been swapped out. I was worried about that as well with my car. After a bit of research I discovered that they were not riveted on back then and that the holes were used as an alignment tool. Have seen a bunch of Canadian valiants (64-66) in a vintage car wrecking yard here and all looked the same as yours (same on my 63 American dart). Can't speak for the fender tag though. I know some things were different for Canadian vs American valiants. Could have just been removed for paint as it appears the car has been repainted at some point. Possibly put back on with different screws.
