What's the 6th digit of the VIN on the dash? Don't need to tell us the whole thing, the 6th digit is the year. If it's a "2" its a '72, if its a "3" its a '73.
Used to be some vehicles were titled in the year that they sold, not by the body. It happened a lot with trucks in the 50's, although I've seen it with cars as well in some states. A '72 car sits on the lot and isn't sold until '73, and is processed as a '73. Unthinkable now, but it used to happen.
Or it could be some kind of body swap nightmare, as already suggested.
If the first picture is indeed your car, I might be concerned. Not only does it have the earlier nose/grille, but it doesn't appear to have the '72 side marker lights. '72's had the "stick on" plastic side markers that stuck out from the fenders and didn't have any metal surround. Yours appear to be the 70/71 style side markers, which were flush mounted and had metal surrounds. Also, the picture of the rear of the car that you posted is a '70/'71 as well.
'72 tail end and side markers...
'71 tail and side markers...