the valve cover gasket is a prime candidate for oil leaks and is easy to replace . (don't use cork and read up on the proper torque specs and torque pattern)
the headgasket usually fails in a more catastrophic manner so I doubt that is a headgasket issue.
added a thing today
no idea what it might have come from originally (just a random ebay special), but it's made from aluminum and finally tells the world I have a turbo Jeep
there's no set rule, but tech Qs from the OP should really get put into the Tech forum because more people look there than the build threads and so more eyeballs = better chance of finding someone with the answer.
I would clean it allllllll up. scrape everything off in the affected area, drill out the spot wells for the frame cap to pull that up, and see what all you're dealing with. if you only have a few tiny pinholes, you're in excellent shape.
need more pics of everything! I have an original Comanche dealership brochure from Venezuela but don't read the language so it's more of less a lot of pretty pictures (non of which include an extended cab)