I found a 1978 L6s in a pawn shop about 3 weeks ago,it,s pretty dirty from use but no cracks,chips,breaks and it sounds and plays great.It's got some kind of stain on the 2nd fret but its not a fill in or anything to care about just a stain the whole guitar needs a good cleaning.The pawn shop got it from the original owner a session player from Nashville.the 6 way chicken switch is totally different from the new ones that just split coils
Here is the original settings
Both pickups, in series
Neck pickup, alone
Both pickups, in parallel
Both pickups, parallel out of phase, with the neck pickup's bass response restricted thought a series capacitor.
Bridge pickup, alone
Both pickups, series out of phase.
and here is the wikipedia page with some good info on it.
http://en.wikipedia.org/wiki/Gibson_L6-S
plus the 3 control knobs one for volume one for tone and one for mids, real different.
heres mine before clean up.
I dont know if it's stock or not but I have a TP6 bridge.