Quality differences is not found with the cotton braided wires provided they use the correct colour in the loom, that kind of wires is easy nowadays to find, but the quality difference is found at the terminals and the conduit for those and the cotton braided cover the harness has. Original the terminal eyes where neat and well suited size for the screws, pressed and soldered to the wire and I guess all had a short black rubber tube as conduit. The black braided cotton cover was knitted on the harness and cover ends where terminated elegant. Weathered bits and pieces can be seen on the Yahoo 101 club group site under albums. Wire harness. Parts of main orig harness
Worst harness I have seen was plastic wires covered with a stiff tar or asphalt tube as cover and standard pressed automotive terminals, sold as "original harness".