Hello Seanmp,
You probably already know this, but what you have appears to be a shotgun produced in Belgium in the period 1890-1920. It's the sort of shotgun bought in and sold by the thousands all over the North American Continent by Hardware and or General stores mainly in the 10-20 Dollar price range. It isn't a quality shotgun as I think you already know or suspect. Evidence of this is the soft materials used, see the 'boogered' hammer screws and the mushroomed heads on the firing pins. The engraving is, so to speak, far from being good quality.
I think that a previous owner was just too lazy to give it a regular oiling on the stock and the metal parts and thought he would save himself further trouble by just varnishing it all over. The same person or another, thought so highly of it he couldn't be bothered to even move it whist decorating, hence the paint.
I'd take it apart and remove the varnish, peen the metal back into place on the hammer screws, reshape the slots and harden them, remove the mushrooming from the firing pins, correct the shape and harden them as well. Notice the hinge pin? it's rotated out of position, something else to correct there.
Refinish the stock with oil or varnish, keeping it off the metal. If necessary re-blue the barrels but don't hot dip them whatever you do or you'll have a major problem soldering all the barrel parts together again.
I'm not being critical, or running your shotgun down, it's just my honest opinion. However, you could ask here:-
(You need to Login or Register to view media files and links) There are a number of shotgun restorers there. So don't just take my word for it, ask around.
Good luck with it.
Harry