Great find...Huge project.
You're right about the absent collector value , even as is.
However, if performed well, the filler + powder coat or durocoat could return a very attracticve and usefull gun, with an intersting story to boot.
Fortunately, current product offerings provide a wide range of colors and surface fnished to suite any individual's taste.
I believe I'd keep to light field loads though...
Keep us posted.