All on your parts list are same for large and small trucks for each year of 48-53 and the similar but different 54.
Your quotes about cabs being the same and or different might be referencing different years, or COE vs. conventional.
For the 48-53, and 54 only the cabs are pretty much the same on all conventional trucks and pickups, so the available restoration parts are the same.
The front fenders, hood, and related parts are different between 1 ton (same as all smaller) and the larger and 1.5 ton (same as 2 ton). GMC front end will be different again for the 400 series and larger again is different yet. Nominally the same cabs as pickup for GMC up to 600 series, Though some small variations exist in firewalls like for diesel in 52/53.
In other words AD Chevy and GMC cabs and interior bits are pretty much the same and interchangeable from 1/2 ton trucks up to a huge GMC 600 series (excluding COE).
