I think it has to do with the lower grille support. I just did the '73 front end to '72 front end swap on my Scamp. Fenders are the same between '72 and '73. '70-'71 had the recessed marker light. So all you need is a '70-'71 hood, bumper, bumper brackets, grille, and lower grille support. '69 Valiant pieces will work too, but the grille looks different.
