Jason, I bought a fresh air heater from 1951Chevy1ton last year, (and he was more than fair, very good guy), all original, was everything he said it was, and the plate that came on it is the exact same one you have in your picture. I would venture to say there were several versions used back then, as there were several suppliers of heaters back then. Somebody that has fooled with more of these than me will chime in and set us straight.
What I bought, if I remember correctly, he said came out of a 1953, I put it in my 51, it fit, I'm happy.
And the defroster decal will probably be the same as the plate. I bought the white letter one from Classic, cause my heater is dark colored. What came originally, I'm not sure. Or if the trucks even had that originally.
Tim Lederman or Brad Allen have a huge amount of documentation on these trucks, but I'll bet either one will know for sure.
I suppose it depends on just how original you want to keep it. 99 out of 100 that will ever see it, wouldn't know.
