Convertible vs. Hardtop Rearview Mirror Question

[JeffAARy]

My 1970 Barracuda droptop is missing the rearview mirror.  The trim piece is there, and there is a ball with a threaded shaft hanging down.  I assumed the post should thread onto this.  However, the posts on the two mirrors I have look like the ball is integral and not threaded on.  Is there a different post for convertibles, or do all the posts have the ball as a separate piece that threads on and I'm just not unscrewing mine hard enough?

[1 Wild R/T]

The ball should stay with the mirror, it is attached by an allen bolt fromthe back side, loosen the allen but don't remove it, then hit the allen screw, hopefully that will loosen the tapered stem that is holding the ball on you mirror post...

[JeffAARy]

I'm not talking about the ball attached to the mirror.  I'm talking about the ball that attaches to the trim piece up by the windshield.  The stems I have look like the ball and stem are machined out of a single piece of metal and can't be separated.  My car has a ball with a threaded shaft hanging down, meaning there must be a stem that does not have an integral ball and is female threaded instead.  My question is are there two different stems, or can you remove the ball from any stem?

[JeffAARy]

I installed a standard mirror and post last night and they work fine, so I'm not sure what the piece I had was or where it came from.

[1 Wild R/T]

Cool!  Glad to hear it. it's been years since I've had mine apart so the details are iffy..