There are a lot of king pin kits available with those same 1.109" kingpins (same length too).
Variations in the kits are brass/steel or plastic bushings, different thrust bearing or bushing types, and freeze plugs or gaskets for caps.

For these 2 tons I have used NAPA # 262-1016 when I need 1.109" kingpins because they come with bronze/steel bushings and with thrust roller bearings both of which I like better than the other options.
This kit is also cheap in comparison to many of the other more or less suitable kits (though looking online they're more expensive now than I thought they should be). However it does not come with freeze plugs which you may need for your 46 axle.
https://picasaweb.google.com/lh/photo/GaoSuiAlD_p0_hJKmsMWhtMTjNZETYmyPJy0liipFm0?feat=directlink

Point of all that is go to your auto parts store and look at all the kits with 1.109" kingpins and see which you like best for the contents and price.
That may or may not be exactly what the book says your model truck should have.

•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-