Negative, my 73 dart sport has the air doors by the feet. It was a non-AC thing, not sure what year was the last for it. I love those doors , they really bring the air in. They suck when you have not opened them in a while and it fills the car with leaves and other crap.
Firewall is different for AC vs non-AC. It also changed in 73. Here is an adapter plate I made to install the classic auto air box in my 73 so it bolts in.