...insert sound of crickets for effect...David, many years ago, one of the first questions I asked on the old Yahoo! 113 forums was this very one. Unlike you, I got plenty of answers. Sadly though, none of the answers had anything to do with the question! They were admonishing the question in the first place, saying why would one want to golf, etc.
Nonetheless, I was a bit alarmed at the amount of space a spare took up, and thought a space-saver might buy some peace of mind and free up enough space for, say, a golf bag. Nobody could answer the question if any modern Mercedes space saver spare had the same bolt pattern and would fit. Collectively, "they" did not know the answer now, and today "we" still don't know. I don't have access to, nor do I own any modern Mercedes vehicles that might have such a spare, so I can't help. I don't even know if any Mercedes were ever equipped with such a thing. Never got an answer.
Maybe somebody with a modern Mercedes will check?
Meanwhile, enjoy the crickets...