1965 Barracuda rear defogger

I have been trying to figure out how the rear defogger worked in the '65 barracuda's, and what equipment was needed.
While doing some research regarding the defogger, I learned that, in the '65 Barracuda it was only available as a dealer add-on. As I understand it there was a blower somewhere in the back compartment, and a shorter privacy panel for improved air flow.
My car has the shorter tilt-up separation panel (which I was told was for the cars with defogger)., and a vent slot in the rear passenger side. But I don't see any place where an additional switch would have been , in or under the dash.
Can somebody help me understand more about these systems, and what equipment and modifications were needed:
Do all '65 barracuda's have the interior vent slot in the rear compartment just below the rear window on the passenger side?
Could a '65 without a dealer installed de-fogger have the shorter privacy panel for any other reason.
Thank you again

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