yet another ignition wiring question

[AngryPirate]

model year: 1961
So, I have been cleaning up my fuse block and wiring, replacing any sizzled wires.

The motivation to do this was to put a proper ignition switch in instead of the backwoods method they had.

Looking at the wiring diagrams posted here ( http://67-72chevytrucks.com/vboard/s...d.php?t=378484 ) it says there should be a brown wire for the accessory that I can plug into the 'acc' prong on my ignition switch. All of the other colors are there, just not the brown. Like looking at 2 different wiring harnesses and there was no brown wire to be seen anywhere near the ignition switch wires. There is a 'tan' wire but it's for something else.

Thanks,
Scott