So I bought a RestoParts rear view mirror. Way too loose on the bracket, so I made shims trimmed so they were not visible. I used strips of beer can glued on with super glue to assist with keeping it in place while pushing into the bracket. I needed to shim both sides. Worked great! Maybe this will help someone.
I noticed my repo doing the same thing, about 3 weeks after install I switched from day to night and the non switch fell off