Ok, so it's a centrifugal automatic clutch. The first P1s in the 50s had a manual clutch. This one is from 63-68 (ish) and has the regular centrifugal clutch.
So that kinda blows for my wheelie-ing bike, but whatever.
The motor lock-out thing is pretty cool, though. That's what my fingers are showing. You twist a knob and it disengages the front cog from the motor, so you can pedal it without drag.
It also doesn't have a perch for the clutch cable housing stop. That's mounted on the frame.
So basically I have a weird motorized bike motor or a museum piece.
Unless I find a 1966 cimatti velocim.