Brake Wheel Cylinder Help

[NCSUDucker]

Looking for the correct wheel cylinders for a 39 1 ton truck. Got a little confused looking at the green bible/searching online. I think I have found the front at CW Moss.

https://cwmoss.com/collections/brake...-right-1939-48

https://cwmoss.com/collections/brake...mbly-1-x-1-3-8

But I'm struggling with finding the correct rear cylinders as most say "except 122" wheelbase"

I can find the rear for a 3/4 ton 122" wheelbase and a 1 ton but it says "except 122".

Truck is at the mechanics right now so a visual reference isn't possible for me, brakes were fading bad last time I drove it. Assuming it is the master cylinder which I already have but wanted to have the parts on hand in case its one or more of the wheel cylinders causing the problem.

Thanks in advance.
Brad