Was gifted a very old Stevens 20 gauge double barrel shotgun. Cannot locate any model information. What is visible is Stevens name on left side above double triggers with a waterfowl in flight. 20 gauge is engraved top of one barrel. What appears to be serial numbers (H44861) are engraved when opening the shotgun.

Lots of pitting on the barrel and missing a top snap screw. Want to bring this old gal, that has been badly neglected, back to life. Identifying the model will assist greatly in locating the top snap screw and a couple of other things that need to be replaced. No good with posting pics, so hope this information is enough for the experts on this forum to get me headed in the right direction. Appreciate !!