OK I watched this thread to see where it would go and I will give you a run down of what you need and what is interchangeable.
#1. If you have a 73 then the rear bumper is the same as 70-72 but the front is different. Only 72-73 has jack slots.
#2. To make a 73-up into a 72 you will need grille, hood, grille support, bumper with brackets. Also the taillights and taillight panel will be different.
#3. If you want it to look like a 70-71 then you are gonna need the 70-71 fenders as they have different marker lights. And the parts from list #2.
You can also alter the 72-up fenders by welding in the correct 70-71 marker piece.
Hope this helps