hi, i have several of these trucks as well, attached are two photos of the 1953 1 ton radiator support front and bottom view. This support is all original and in good condition with no cracks or welds or rework. the radiator that was bolted to this support (not in the photo, it's behind me where i took it) is the normal size radiator.
This 53 radiator support is nearly identical to the one in my 1950 chevy 1 ton, which does has the oversized radiator option. Both radiators will fit interchangabley in the same support, the oversized radiator also comes with a shroud to help force the fan air through the radiator.
The only difference from 1950 to 53 that i could see is that there are NO water drain holes in the 50. If you look closely you can see there are rocks stuck in two little holes on each side of the mounting bolt flange. In 1950 those holes don't exist and this part fills with water and rusts out, sometime between 50 to 53 GM decided to make holes to allow drainage, i have since drilled holes in my 50 to let it drain out too.
This part is slightly different in the GMC trucks, the top is changed to accommodate the much different shaped support for the tins and the GM radiator. So don't pull one from a GM thinking it will fit your Chevy. -stan
