Wasn't sure whether to post here or in electrical because it touches on both. Finally found a set of new (used) shift rails. They came out of a GM np205 that, as far as I can tell, the only difference was the donor np205 had an indicator switch for one of the detect bolts. After I got the rails removed, I noticed the notching was a little different. Same place, they just looked deeper on my original bent one. At first I thought this was just because it was worn out, but after some research I discovered this was the design. The shallower notch is to activate or shut off the indicator switch. I'm assuming I can still use that rail in my np205, just need to use the switch detent instead of the bolt detent. Let me know if my assumption is off.
Now for the electrical...I have no idea whether my 1979 K20 had a working 4x4 indicator light. I tore into this truck shortly after I bought it and never tried it. I can say that - as noted above - the t-case did not have a switch, but the little plastic piece that goes into the cluster (fasten belts, brake, etc.) included one for "4wd lock." Maybe it worked and the indicator switch is somewhere other than the t-case, maybe it never had a light and the cluster has been swapped, maybe it was installed on all clusters but only used on certain configurations. Would a 1979 K20 have come with a 4wd indicator? If so, where would the switch be if not on the t-case? If it did not have one before, how would I go about hooking this one up?