Assuming the barrels are intact this is an E grade and if cleaned and mechanically perfect it is about a $1500 gun.
Remember one barrel doesn't cock and the forend is missing the tip piece.
I would not just leave it at that. I would have Buck Hamlin or Keith Kearcher clean it up, repair whatever is causing one barrel not to cock, repair the forend and leave it at that.
That should not cost all that much. But it is much more valuable if properly cleaned and mechanically sound.

Great-Great Grandson of D.M. Lefever
www.lefevercollectors.com