Stop in for a cup of coffee
You know it's kinda odd that I have been googling 74 dusters and I have found quite a few with the 75 grille.
I wonder if late in the 74 model year they started using 75 parts. 74 was the highest number of dusters ever produced in a single model year so they had to have been flying out the factory doors that year.
That would explain why my 74 duster shell has the bump in the floor for a catalyitic converter which is supposed to be a 75 + thing