'67 Camaro Factory Rear Speaker pic???

[Mark_C]

What kind of radio mast? Assuming it would still be original a single piece mast is an AM/FM, collapsable mast or a rear mounted mast indicates an AM radio. If your trim tag is coded for the U80 speaker, then an 8 track is out of the running since the U80 option was part of the 8 track package (at least in 69) and your trim tag would be coded 2U for the 8 track instead of 2R for the aux speaker and you would have 4 speakers in the car, not 2.