Ivory color admirers,
As to my knowledge, the ivory-colored shift knob was not available via data card ordering but you could get it from the dealer's shop if desired.
The ivory-colored seat levers are definitely not original, the SLs always came with black ones.
These parts are no typical SL parts but the tip of the turnsignal lever from the Ponton. Since that older car generation was typically delivered with ivory steering wheel (in the 50ies), the gear & turnsignal levers just matched.
The ivory ones might still be available - I don't know, the black ones (128 545 04 35) are definitely not.
On the SLs (stick shift or automatic) you have just to pull off the knob. A little difficult perhaps but works.
Best,
Achim
(Magdeburg, Germany)