Looks like it should clean up OK, though you'll probably have to replace much of the exhaust system (I think that model year has the under-transmission 'muffler' as well).
I think that it used to be an R80RT, of 1985 or later vintage, judging from the monolever swingarm, oil cooler and wheels/brakes - that someone converted to a 'naked' bike (perhaps b/c of fairing/fiberglass accident damage) with an earlier model headlight bucket (ignition key on headlight ear). If the engine internals aren't rusty, it could be certainly resurrected if you have the time and patience. The price would have to be reasonably low.