Hello Frank,
Ivory colored steering wheels are clearly supposed to be "ivory" and not white.
There are some little differences in the horn pad shadings though.
It mainly depends how old (and faded) your horn pad is.
BTW: The very early 230 ones where supposed to be "elfenbeinfarben" (ivory) and later ones (230 SL from VIN 002000 or so) "hellelfenbeinfarben" (light ivory). If your's new, it should be the latter.
Have you looked at it outside with daylight?
Usually a washing (mild dishes detergent) and some buffing helps.
Best,
Achim
(Magdeburg, Germany)