Upper Control Arm Eccentric / Cam bolt location

Hello- While cleaning up and painting the upper control arm cam bolts, I noticed two are stamped with an "A" and another "B" and another "C".

Upper control arms and bolts are from a 73 Duster, going on my 67 barracuda for disc brake conversion.

Are these marks to locate the cams L/R and F/R?

:scratch:

The markings lead me to believe there is a front or rear common on each side (A) and b and c for left and right in the other position. Searches here and on google reveal nothing. Does anyone know if these markings are meaningful?

Thanks! -Chris