Perhaps later models were a slip fit.
Just double checked the original ones in my 51 GMC and they are riveted over, and recall the same on the 52 when I replaced them.

Thanks for the part numbers and resources.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-