Rear air question

[RustyDusty]

I have seen photos of factory rear air that has the blower in one speaker hole, and a duct ran in between the speakers. My 76 has the rear air switch, but this ugly thing installed. I take it that this is aftermarket?

 

[1970Duster]

Starting in 73(?, but by 74 for sure) the rear defroster switched to the modern grid style kind.

 

[RustyDusty]

Did they still call it "rear air" on the switch?