Can't help you on your 67 but the paperwork and patina for the 68 shifter knob suggest that the GTO crown shifter knob was used as a firebird option as well. Go figure.
Kevin-
Restoring and maintaining old cars and old boats....oh what fun we invent for ourselves. Seems to go in stride with ....You don't live it until you own it....Three steps forward....two steps back ....