But be careful what you're calling the "origin." If your genny has little metal tags crimped to each lead with the supposed identity of the lead stamped on it, then, in the words of Ronaldus Magnus, "Old Russian Proverb: Trust but Verify."
Just learned that one while replacing the doghouse on one of my ST5s with an 8x8 plastic connection box in the lid of which I set a 120V/20A duplex receptacle and a 30A L14-30R receptacle that I now use to connect to the manual transfer switch. As I disconnected each lead from the yellow terminal board I labeled it with marker pen on masking tape wrapped around each wire. Then, once the old doghouse was where it belonged (in the trash can), I fed the wires through the bottom of the new box and (forgive me while I wax poetic):
What to my wondering eyes should appear,
But little metal tags crimped to the leads
That I hadn't seen before!"
I looked at the tags and found that the numbers on them bore no relationship to where they had been connected on the yellow board. That had me scratching my head for a while. I finally ran that by George and he confirmed that although the leads may be marked that way, they are frequently mis-marked, so do your own investigation. I did so, tracing them visually and with a multimeter.
q.