[urq] early style pneumatic diff lock knobs

[Charles Baer]

Just picked up a new diff lock knob from the dealer for $4, blecch.
It's really a knob, not a nice flat disc that's easy to flick in and out 
with
two fingers while on the move.

I've seen the various replacement controls but for the time being I'd just
like to find an original one without stealing the one out of my 4K.

Anybody have a source for one other than the dismantler yards ?

Charlie