I have two of the three radiators out. Here is the tag from the radiator out of the 41:
The tag is decoded: first two digits: year of manufacturer. Then the part number:
Here is the tag from the radiator from the 43:
This kinda give the info I have about the trucks even more credibility... the 41 is looking more 41-ish and the 43 is looking more like a 43.