This is for anyone who runs across this posting on a web search
The A-12G Stands for Alnico magnet 12" Guitar Speaker
The 67 is the identifying number for Eminence Speakers (You'll find this number on all Eminence speakers)
The 7824 stands for the 24th week of 1978
It is my understanding that these are 75 watt at 8 ohms and were used in Music Man amps during the first five years of production. I use a 1978 212-65 with these speakers in it and it is a real screamer. However I have to have the cones in these glued back together about once a year.
I too have a Musicman 212-75. I got it new in '81 or '82. At a gig once, it fell on a light tree and tore a hole in one of the speakers. I replaced the C12G 67-8110 with a celestion G12T-75, 8ohm speaker. Do I need to run the amp on the 4ohm switch? I think I just assumed the speakers were 8ohms. Is C12G 67-8110 an 8 ohm speaker? Could it be 4 ohms?