Jeff - thanks for looking. This is for my Oct. '68 San Jose built Grande. I talked with Rhode Island Wiring today. They are thinking, as you suggested, that the finished loom was coated with something that has worn off. Actually, I have suspicions that the loom may have been "cleaned" in something that took the coating off. There is no trace of a black coating except under the tape at one end.
I sent it off to RI. Not sure they can do the brown/black weave then coat to black so I may have to settle for just a black weave to look like new finish. I would have just used the AMP repro because it does have the black woven cover but, as you may know, the molded connectors have a different appearance so might as well try to get it right.