Strange bar and actuator in the back

i set up a survey in the general discussions so everyone can list what kind of vents (openning of fixed)they have and if they have an ac car or not.

Here's what i found in the 72 service manual. Under the heater section a vacumm diagram showing vacumm lines rinning to the astro rear door valve on the right side of this door in coupes and the left side on convertibles. There is no vacumm line running to any rear valve shown in the AC car vacumm diagram.
In the body construction exploded view the center panel with these opennings are shown. There is a baffle and plenum shown. Both of these items show having a diferent part # for cars w/o air. i will research these part #'s and see what i come up with.

G'Day everyone
I have a 75 t/top non a/c the vents on my car work when you select the vents on the heater control left hand dial.

I have a 74 coupe with air. The vents are nonfunctional and are not even cut out. They are just the grilles on the back deck.