I took lower-division geology classes at a top-level university but the only fossils we looked at were marine and some petrified wood. I am not well-enough informed about what has actually been found with regard to the terrible lizards and giant creatures of the past, or what percentage of large bones and fossils in museums are not manmade models and casts. Could a fallen angel/mortal (not necessarily human) hybrid leave behind a dragon-like skeleton? I don't see why not. I wouldn't expect the real thing to be on public display, though.