Already done. The only reason I replaced the older one after so many years was the mirror began to "tarnish", or more accurately the mirror surface began to rub off. I know about front-surface mirrors from my photography days with old rangefinder-focus cameras.

When I bought the new mirror a couple of years ago the first thing I notices was that it was a rear-surface mirror, that is, the glass covers the reflective surface. Works the same as the old one, but less chance of of the reflective surface wearing away.