Hello,
I recently rebuilt/replaced the control unit/cables in my 1969 280SL, and found that this particular MBZ OE part to be very hard to source.
I ended up using a reproduction part sold by Buds' Benz.
You appear to have a 230SL? Might check first to see if parts are interchangeable with 280SL (I know levers are different).
Since you have it apart, you might want to change out the cables as well; made a big difference.
Galen