Carl - Here's an extract from the
1952 Chevy Truck Data files that lists all the tire, tubes and wheel specs as well as pictures of the 3800 series rims.
There is a difference between the single wheel vs dual wheel models, so important to know which he has before starting the hunt.
The wheels are 3 - piece, main wheel + side ring and lock ring. See the 2nd screenshot below from a 1929-57 Chevy Master Parts Book for more details.