JP,
I also have a 230SL with a hard to find color...#113 "bronze"...when searching for the color about seven years ago, my installer called GAHH. They let him pick ANY vinyl from their book as they make the interiors from flat stock regardless. I ended up with a Porsche brown that was very similar. This was when I was buying the entire interior from them, however.
Please see the pics below...the seats are the Porsche color and the ash tray cover is original to the car.
Good Luck!
Kevin