pulled it out from a 77 comet. i'm thinking its somebodys add in but i dont know who was making the radios for the 77's...this ones by motorolla. I know the earlier ones were made by philco...
I can't answer your question, but I know for sure that the '76s had philco radios. As the '77 year was basically a carryover year, I'd assume that they wouldn't change much.
when i removed it, all the plugs for it looked factory. hooked up very nicely even if it isn't factory is it worth something???