The old Gibson SG Custom had 3 pickups and a 3-way toggle switch. There was also a 3 pickup Les Paul with the same wiring. The positions were:
1-Neck
2-Middle & Bridge
3-Bridge
The old 3-way Strat switches WERE wired for each pickup individually. It is actually the same switch that Tele's still use, only wired differently. People used to put it in between positions to get two pickups on at the same time. That is why they came out with the 5-way switch.
-Stan