I just bought this heater off ebay, I think it is a firestone brand from what I have seen in one post? Were these factory or dealer installed? The heater core outlets and mounting bolts line up perfectly wtih my firewall so I would guess this what my truck had. I cant afford an A/C unit right now but have to have at least a heater and defogger so I got this one to use. Look correct?

 

It's a dealer install. If the truck didn't get the Magic Air heater, then something like this heater was used.

 

No magic air in this one, the side plate in the firewall is still there from the factory. This was a 5 star cab too, I would of figured it would get a heater.

 

Back when, heaters were installed by whomever needed a heater, not necessarily the dealer. Lots of aftermarket brands. Since your truck appears modified, the heater being correct should not be an issue. A working heater in your area would be a requirement.
As late as the 1960s, heaters were optional. I know of a 1960 Chevy Impala, top of the line, that had no heater.

 

I have a BFG heater that is pretty neat looking.I also have firestone and BFG radios I have found.I grab that stuff when I can, all mine seem to be 6v.If I can find them I will take a picture.