200e

I noticed on some pictures that some people changed the knobs
on the 297 Infinite Phase Shifter from the white Selco knobs
to the old school Rogan knobs (6 small ones, 2 medium ones and one big red one) . 
So i was asking myself if someone here has those knobs for sale
or could tell me where to get them.
I am of course willing to pay a good price for a set:)
Thanks 
David