Thanks. I have a GM parts book but it is a bit of a head scratcher when it comes to hood mounted tacometers. The GM Pontiac parts book listing has no hood tachs listed for anything before 1968 under group number 9.750 and even then it only lists parts of the tach such as the glass the fiberglass housing or wiring harness. The parts book listing for the housing is listed as 6469017 and it is listed as fitting both the GTO and the Firebird 68-70.
Could it be the hood tach for the 67 model was an RPO dealer installed option only? I have come across similar listing in the parts book like the rare map lamp option. My car has them but in the parts book the only serviceable parts of the lamp are the switch, lens and bulb.