A couple of things going on here. First, as you pointed out, its apparent or pictures suggest that the drivers side inner fender panel has been replaced since it as a visible, stenciled part number on it. Also the date stamp on the drivers side fender suggests that it has been replaced supporting the idea that there was an accident and additional parts and panels were replaced. IMHO good chance the hood also.
So we have that and the fact that the VIN on that side is not where it typically would be located. Guess you have already looked at the bottom side to see if its been cut off the original panel and location and grafted in to area over the shock tower as shown. No reason, since the original panel would have been in place, for the operator not to stamp the forward and rear VIN on that side where always had and did
Have you checked for the other two VINs (6T07A161171) stamped in the inner fender panels? . Both behind the shock towers on the rear inner fender panel upper lip as you likely already know
Looking at other cars around the same 66 production period at NJ I found no others with a factory VIN located where this car currently has one but you knew that and that is why you asked
Interesting but have seen similar things owners and repair shops have done in the past
