I'd go with the ID plate, as it looks original. Not a 1947-50 cab as it doesn't have the side cowl vent. The Panel trucks were a bit of a specialty (fewer made) and they might have been using up older parts, although 1950 non vent window doors in 1952 would be kind of a stretch for that. Prior to 1952, the bumper should have been chrome, not painted, even on plain-jane trucks. The painted bumpers were used in 1952-53.
So I'd have to agree with jimgmc, that the doors were changed at some point in it's life.
