They are out there . Any parts store will be able to help with the numbers.
Good luck
CR14866 If you can find them. found mine on Ebay
National #480630 easy to find.
Its a one way seal will let grease in but will keep oil out of axle tube .
Make sure you have the knuckle greased right .
These numbers are for half ton and 3/4 ton


!956 Gmc Napco 4x4 Factory line built .