I've junked more of those dang old spotlights, and had to fix hole in window frame too! Later year, thinking 67 Chevy SM420 4spd is only one with back-up light switch in cover. Not sure if you can just swap covers to others or not. I don't see why you couldn't use a brake switch, lever type like on your truck that gets hit by the brake pedal and use it somewhere that pushes on it when putting the 3spd linkage into reverse. Maybe mount on firewall and have linkage hit it??
For the lights, you can buy clear lights at most auto places or truck/trailer places and wire them in, mount somewhere in back and use a fuse on hot side, your in!
