Hello,
Yes George, this is how I do it also.
Another bit of information while we are on the subject. Many of you may notice that the reflectivity of your side mirror glass has deteriorated over the years. To resolve the problem, remove the glass and use some chemical stripper to finish removing the black coating on the back of the glass. Use a wood or plastic scraper to finish removing the coating. Repaint the back of the glass with some black spray paint. You will notice that the mirror is restored. The reflective coating is actually between the black paint and the glass and stays intact.
When the paint is completely dry tape the back of the mirror with some masking tape or duct tape to protect it from the spring. Install as usual. Just be careful not to use a metal scraper when removing the black coating or you will ruin the reflective coating.
Or just buy a new glass from Mercedes, they're fairly inexpensive.
Joe Alexander
Blacklick, Ohio