According to the schematic there are two 'resistance wires'. The one that Rukee refers to and the one located on the passengers side of the firewall. From the information that I am starting to get is that the 'resistance wire' cuts down the voltage that goes to the points in the regulator. I assume that this is necessary to avoid burning up the regulator points. This wire is in excellent condition with no signs of overheating. Unfortunately this car came in boxes and I did not have the opportunity to see it in use.
On another note I cleaned the terminals, plugs connectors etc of my original harness. All wires prove out to be in excellent condition, very pliable, no signs of heat damage, or cracking. Sure is a good way to learn about the wiring. Once you go through the harness a few times you get an appreciation of how relatively simple it is.