Gotta on the questions.

The old Stude truck looks pretty good too!

Can't speak for the Stude trucks, but in terms of 50s Dodges, the cab corners, especially the floors in the cab corners, were favorite places for mice to nest, so often there were holes. The step area may be a concern. The late 50s Dodge step area on the cabs were structural pieces that supported the cab floors. once the step area rusted out, the cab floors were pretty weak and would sag, and let the door jams move under the weight of the opening doors, but the step area would have had to be pretty shot for that to happen.
The Dodges of that era had the sheetmetal of the fenders folded over at the back fender edge to double up the edge to give it extra strength (think 60s performance car door bottoms except at the back of the fender instead)). Only problem was they didn't bother painting or rust proofing the metal before they folded it over, so the lip rusted out. I suspect the Stude is the same way. I'd be really surprised if there were any replacement body parts available for that cab. The extra front sheet metal and the extra box is a plus.

On the positive side, the 50 Stude should be a bigger cab then the 39-47 Dodge truck cab, and defiantly wider then the 35 Plymouth. Another advantage is its a truck. I think trucks lend themselves to modifications easier then most cars.

I'd make sure the other guy gets the title straightened out, that can be a mess. Gene