72 chevy k series reverse light wire routing

[Seventy468]

I am working on my brothers 72 Chevy k series pickup and was wondering of the factory wire routing for the dark green/ light green wires for the reverse lights for a sm465 4 speed trans. I have an idea on how I am going to run them (probably along the speedo cable for cleanliness) but I wanted to know what the factory did, as the wiring was a little funky on this truck and I have nothing to go off of, and did not see anything in the service manual. I found some descriptions using a search but was wondering if there were any photos out there?

Thanks

[B. W.]

Only pic I have shows the wires dropping off the passenger side, I believe they run up the firewall then over to driver's side but don't know exact routing. I know the rear harness runs down the driver's frame rail, not sure how these wires get there.

('70 K20)

[Seventy468]

excellent! that tells me a lot actually. Thanks B.W.