Your bird is probably an early 68 build so it came with a different door hole for the remote mirror. We call this the Type I - round mirror. Type II rectangular came out mid to late 68..
You need to get round mirrors or a new door LH skin.
Here is a pic of the hole in a door for Type II mirrors: (couple of extra screw holes)
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________
