Yes, they do. But it is easy to do yourself but you will need the mounting kit also.

On my 99 c230 the fiber optic and connector were in the trunk right hand side. I bought a used MB changer on ebay. Mine would not recognize the cd changer no matter what I did so I took it to the dealer.

When I picked the car up that told me that the cd changer was fine but my radio was defective and wasnt communicating over the datalink. They changed the radio just to be sure and it worked but I didnt want to spend $580 for a new radio and just resold the changer on ebay as "tested"