Yes, FLAPS should be able to get you the u-joints. I had to get some for my 53 1 ton. I'm replacing all of the u-joints. By the way, I found out when I had to replace the u-joint in my 09 Chevy Colorado, that the rear u-joint is two different sizes! The caps in the rear end yoke are a different size than the ones in the end of the drive shaft. Didn't know that was possible, but now I measure both ends carefully.
Tim
I am currently digging back in to a 1953 3800 (one ton) with a nine foot bed. I've owned it since 1979, and drove it until 1982 (or so). My wife got me involved in restoring it back in 2002, got the body removed and the frame redone, then things came up. Now I am retired and starting again. If anyone is interested I have photos on Imagur (
https://timwhiteblues.imgur.com/ ). I live way back in the woods in the Ozarks on 40 acres at the end of a 2 1/2 mile private road.
Tim