Rear Air Differences in Same Model Year?

So I’m in the process of restoring my 73 V8 swinger, which appears to have factory rear air but the original toggle switch was missing from the dash and some previous owner put a cheapie plastic one in its place with a rats nest of wiring that will be removed.

But my question is, on my V8 car the rear blower motor is mounted in the center of the package tray but on my slant 6 parts car (also a 73) that I robbed the factory switch and complete wiring harness from the blower mounts in the pass. side speaker cutout and has a hose that goes to a long slim vent in the middle of the package tray. It was a working setup which is why I took it off the parts car. Were there differences in the same model year for the rear air option? And if so will the harness work with my V8 cars motor? I can post pics to help if needed. This is my first Mopar project so I’ve yet to learn any small details like this.