I don't know about Napa, but I bought mine for my '52 from Classic Parts of America, (formerly Chevy Duty). Cost was 119.95 plus S & H, parts number on my invoice is 73-061k, Roller Bearing upgrade kit. It was a direct replacement on my truck. Hope this helps.

1952 Chevrolet 3100 1/2-Ton
1946 Chevy Pickup Truck on an S10 frame (It IS Finished!)