47-55.1 1/2 ton OEM differential side gears needed

[RMR]

I'm doing a full restoration on a 1950 Chevy 3100. The rear differential has been a challenge. The factory axle shafts and side gears have bad splines. Got a donor set from another truck. The splines on this set are good, but the teeth and thrust surface of the side gears have some chips and rust. I'm not seeing the right side gears and valuable anywhere. There are 17 splines in the center hole and 16 teeth around the outside face. None of the ones I'm seeing on ebay have that combination. I have seen plenty for 3/4 ton and up as well as for the two speed rear. Any input? Anybody have a set?

(I know I could have just put a different rearend or any number of non-OEM options, but the owner wants it just like it left the factory.) Thanks!