It almost sounds like a 1954 Chevy passenger car ignition switch. As shown in this photo of a 54 bezel, the far left position was Lock. This was the only position needing a key. If the key was removed in the off position, the car could be operated on/start/off without a key. And because there is very little securing the orientation of the switch, the lock position could easily be rotated to 12:00.
As best I remember the Lock position mechanically locked the ignition switch only. I don’t think the accessory electric position had been developed yet.
Hopefully someone with more direct 1966 experience with chime in.