It has two little allen set screws at right angles to one another. It might be a CB antenna but it really looks like an autozone special. Keeping it in place until I sort out what's underneath, what's missing and what I need. It's better than a big whole in the fiberglass (which is what a '74 had that I looked at recently).My curiosity was from the appearance of the antenna made me wonder if it might have come with a CB. Being an aftermarket antenna explains it..