I need a replacement also...
As LockDoc mentioned above, if you replace your mirror with regular mirror glass, you will not have the day/night feature since the day/night mirrors use prismatic glass. Below are some links that may be helpful. The first is to a Camaro forum (CRG). It discusses removal of the glass, says mirror glass for 67-73 Vettes also fits 67 and 68 Camaros and gives a couple sources which are in the 2nd and 3rd links. The 4th link is to a mirror restoration service.
Does anyone have access to a Camaro or Vette from the years mentioned above to compare mirror size with a mirror from our trucks? If I had access to the size of the truck mirror, I'd call Paragon and Zip and see how theirs compare. Of course, that alone wouldn't guarantee a match, but it may warrant further investigation..
http://www.camaros.org/forum/index.php?topic=8266.0
https://www.paragoncorvette.com/p-35...ror-glass.aspx
http://www.zip-corvette.com/67-73-in...ent-glass.html
http://www.mirrorladypa.com/Mirror_R...phrata_PA.html