Wetsern Electric 41BB 41AF 41AB 41S 41DK

They're going to be proprietary part numbers for Western Electric.
They did it so only they would be able to repair the equipment.
They may be generally available parts, or ones made for a specific purpose for
Western Electric circuits.
Only way you're going to be able to find out, is to Google around and see if you can
come-up with an old Western Electric part number cross reference.
I had a bunch of Burroughs part numbers like that, and some old employee had
posted one of the Burroughs part number cross references on-line (that had most
of what I needed).
good luck