I did buy Muth mirrors, but they didn't fit. I have aftermarket second gen mirrors, and the glass is about 1/4" smaller than stock ones. I was planning on selling the Muth mirrors after finding out they didn't fit, and of course, dropped one. I heated the LED housing, pulled it off, pulled the glass off my mirrors and glued the LED housing on. The end result was pretty close to Muth's. The glass doesn't have the sanded portion for the LED's to fully shine like Muth, but besides that they work great. They shine good in the day and great at night. Aftermarket LED arrows don't shine bright enough. If you plan on doing this then buy some Muth LED's w/ housing. You may be able to contact Muth and buy just those parts. I notice Muth also sells stick-on external arrows. You could buy a pair of those and tear them apart to get to the LED's also. I'm happy with my end result. I've got a thread somewhere around here.
I was planning on doing the above but it's too involved. Angling the LED's and all that stuff. The Muth cases have angled holes already so it's pretty simple to put them on.
The factory glass on second gens just pops right off. First gens are glued on VERY tight and won't come off without breaking the glass.