I bought the wrong gaskets for my car, mine is a 2002.
So I have a pair of 1996-1999 W210 side mirror gaskets.
I initially put them on my car before realizing they were the wrong part.
I also cut out the opening in the center to make room for the electrical connection.
These cost me $50 on eBay. I will sell them for $25 including shipping.
Here is a link to the parts on eBay:
Mercedes Benz W210 OEM Power mirror rubber pad 2000 2001 2002 Gaskets Seals
I can't upload pictures, but I can send them to anyone who is interested.