You are correct, Otto, and that was an error on my part of writing the nomenclature.

on both versions of the wiring diagram its written as:
NAT. BLK. & RED CR.TR.
I agree TR makes sense that it means trace and is the alternate color for the wire. But I still don't understand CR. Some of the wires in the digram just have TR. with no CR.

And then I study the diagram some more and see another wire (for the high beans) the wiring diagram reads:
12 NAT. BLK. CR. TR.

With no alternate color listed as a tracer

also, confused about what "cross" klhansen means about cross?

so from this High beam wire description one might say that high beam wire is 12 gauge with the natural cloth cover with a black tracer.

Would that tracer be woven into the old cloth cover? I just looked at the one remaining piece of cloth wire on my truck (the wire down the steering column for the horn) and it's just natural with no detectable tracer color...that tracer could just be faded after 74 years, I guess.

1951 GMC with positive ground. Engine is a ‘54 Chevy passenger car (Serial Number 0024472F54Z) with a ‘56 head (casting code on top of head 3836848 GM 4), Casting Code (on passenger side on side of head B56 848 850)