if it doesn't specifically have to be a 72 grille, they will interchange up to 1976. expect them to be very expensive though. ebay has a few for $100. better condition ones are 300-400 bucks.
the 77-78 will also interchange but then you have to move the front turn signals into the grille and use the 77-78 front filler panel below the grille. the 79-80 grille won't work without the 79 headlight bezels/cups.
I got lucky in my local pick and pull had one last old 78 dodge. pulled the grille and filler panel for under $100. I'd check there too if you have one near you.
btw, search ramcharger as well when you look.