Heater core r&r 66 barracuda with ac

It is just the vents, looks factory to me. I have the original buyers order and AC is listed with the other options like power brakes etc.

Then you have the factory integrated heater/AC system. I know there is a bracket in the front that holds the heater unit to the AC unit and that may be the only thing holding them together. The heater unit will have the J Bolt(s) and one or two nuts in the engine compartment that holds the heater box in place. The blower motor comes out with the heater box. This is going from memory here so you still should consult the FSM.

EDIT: If you don’t have the FSM, it’s a worthwhile investment to get one. My Mopars might have one available for free download