Mural restoration and clear coat/diamond seal?

[Kaliharicruiser]

I'm painting my 93 Kalihari and want to restore the mural on the back cap. It's basically intact and has peeling clearcoat or sealer on it- seems to flake off with my fingernail. There are various products on the market to "restore" clear coat- all seem to not really do the job but can remove some of the flaky loose stuff. Also, there is a company called Ugly Sheild advertising sealer removal- they refer to diamond shield or 3M shield on the caps of various motorhomes- including some Monaco products.
I'm in San Francisco and have some artist friends who could retouch the original airbrush timber wolf if needed, but I'm still unsure as to how it was sealed in the rig. Does anyone know if the murals on the back cap were clearcoated or sealed with diamond seal or 3M sealer or something else?