76 Duster Fender to a 72 Duster

Directly? Sure...
The antenna mount is different. Do you intend to use the 70-72 grille? If so, there is a small tab on 70-72 fenders that is there to support that wide, flat steel panel that supports the top of the grille. You can make a tab and weld it on, not a big deal.
A 1972 Fender is actually a ONE year only fender. It is the first to have the corporate all plastic surface mount side marker light and the last year of the grille used from 1970-72.