I have had it apart as far as I can take it without breaking anything. What’s baffling me is that the post that the link arm pivots on is itself free to rotate but will not pull off. So this outer closed end shell spins as a captured part on a pin which is fixed to the mount body. I don’t know how the inner pin fixes to the body, whether it is integrally cast as a feature, or pressed in, or threaded in. My reservation about just drilling in is that I don’t know what the diameter of the inner pin will accept if I want to tap into it. I’ll take some photos as I tear into it and post them here.