Voltage Regulator / Alternator harness issue

Hi everyone,
I have a question regarding the Voltage Regulator and Alternator wiring harness on my 70 Mach 1. Currently the VR and alternator wiring is bundled with the headlight harness. I have since found this to be the incorrect harness for my car, probably from a 69 mustang i was told. I do have the original headlight wiring harness which contains, marker lights, parking lights, headlights, sport lights, and horns, nothing else. I was told that the voltage regulator and alternator wiring for a 70 Mach 1 originates from the firewall under the braces and goes out on the passenger side of the engine bay. I have a wiring diagram and after studying that, found the green with red stripe and black connector coming from the firewall with nothing connected to it that I think is where the VR/Alt harness should connect to. One fellow that i was talking to said that there is no individual wiring harness for the VR/Alt, and that the connections for the VR and Alt are part of the harness itself. He went on to say the previous owner must have cut the wires somewhere and i am looking at potentially rewiring the whole under dash harness. But if i am reading the wiring diagram correctly there should be a wiring harness that plugs into the green-red/black pig tail and goes to the VR and Alt.

Can anyone shed some light on this for me? Possibly take some pictures of that area of the wiring harness so i can see what it should look like properly configured? I am completely confused at this point. Any help would be greatly appreciated.

Cheers
Gos