Thanks for the split. I recalled the discussion and was focusing on these wires and their correct layout today. It helps tremendously to see at least one example that appears to have been untampered (and it is a GT harness as well PLUS what looks to be an EARLY Convenience Group optional wire OR Power Top wire taped to the main harness).
Nice picture(s). Very helpful.
If I understood SpecialEd correctly, he was under the impression that the RH horn wire(s) he has seen with the "blackout treatment", that the treatment (coating) may have been a brittle, flakey substance, similar to the firewall sealant (the sealant sprayed onto the harnesses and bolts penetrating the firewall). In this example with pictures shared here today, we definitely see no signs of overspray on the radiator support or the wire.
I wouldn't likely rule out the use of nor the seemingly obvious conclusion of "no coating used on any examples" if the possibility that only the wire (all by itself) was shot and over time, the coating became brittle and falls off. In that scenario, we MIGHT not find any or very many examples with easily seen signs of it left. Food for thought anyways.
Because evidence suggests NO USE on enough examples, the clear choice would be to leave it OFF of my build at this time.
This was an unanswered nuance that I recalled from the discussion a few years ago and thought it a good topic to revisit.