Should I be posting in the SL forum?
 

I usually get great feedback on my 280SEL but seems like no one knows/cares about the SLC I just got. Mabey the board is just dead the last few days. In any case I'm still looking on advice on a 1973 450SLC I just aquired:

http://www.peachparts.com/shopforum/vintage-mercedes-forum/101451-new-mbz-added-fold-today-pic-questions.html

Believe it or not, small parts like knobs and switches are available from MB. I got some from calibermotors.com/Tom Hanson for my W111. I got a new Hazard knob for under $4 and a vent knob cover for $13. Kinda pricey but available and in perfect condition with warranty, I don't know what kind of warranty you'll need for knobs though.