RJG
So yes there were two types.
1 the extended version was for the non defroster cars
2 the cut off version was for the defroster cars to get air from the trunk area that was suppose to be warmer (maybe who knows) and blow through the vent to the back window.
If anyone has pictures of a defroster set up please post them!
Thank you, that is very interesting. I have only seen one set of dash switches for the heat. Do you now where the switch for the defroster was located, or what other extra material/equipment would be in those cars to make the defrost?