30-31 Emergency Brake Cross Shaft

[Vic in E-TN]

I am trying to put together the parts for a chassis. I have an Emergency Brake cross shaft that someone cut off the end of the passenger side lever arm. I bought a pair at the Fletcher,NC swap yesterday. The arms were different lengths than the one I had. It is almost impossible to read the part number of the arm.
1. 2 3/4 in from center of shaft to center of arm where the clevis and cotter goes.
2. 3 1/2 in from the same points on the other arm.

I cannot find a reason in the Restoration Guidelines. Does anyone know why and possibly the timeline for the part differences.

Thanks.
Vic