I'm purchasing a harness and additional cloth covered wire for my 51 from this company.
www.brillman.com

They're close to me and have a very impressive shop, machinery, and inventory. They also know their stuff, and like old trucks too. Pretty sure they'll know just what color and style was original for your tuck. If I recall correctly he explained that some of the yellowish colored lacquered cloth wire as some companies use today for restorations is not so much original but what the original faded to in time, actual original was more of a white. You can get the new/old wire either way, and the electrons don't care.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-