Yea, I don't recall if the vehicle I got my spare antenna from had a/c or not. Also, it was a '77 Cutlass, so possibly a little bit different than a g-body.I have the new cable to fix the power antenna and just need to get the motor out so I can fix the one I have. The antenna motor runs well and reverses when the radio is turned on and off. The nylon cable inside the mast is broken and the antenna will not retract so I need to get the motor. I don't want to take apart half the passenger side fender just to do the antenna repair. At least it is broken and stuck in the up position so I do have radio reception. The picture is with the outer fender pulled out enough to get the motor out but the bolt head is on the engine compartment side of the inner fender and blocked by the air conditioning equipment.
Side note: I got that antenna as both a spare, and as practice to remove one from my '79 Elky, which has a broken cable inside. Like your's, my motor operates, but will not raise/lower. Mine is in the down position.