Alrighty, figured it out with the help of a Morgan tech. The cap does indeed thread on but it is loctite'd to hell.
First I tried a strap wrench. NOT recommended. Not only did it not work, I gouged a bunch of paint out not realizing how close the metal piece was to the bodywork... This little project just became more expensive.
Final solution: Grab a piece of non-marring pipe and use it and a hammer to tap on the base of the hinge of the cap (closest to the front of the vehicle). It'll slowly rotate. A few taps in I had enough clearance to reach both bolts. Once done I tapped back the other way to realign it.
