I suggest you call or email Steve at this link with pictures of what you have. He is the foremost expert on old Winchesters, Marlins, and the newer Rossi. What you have is a family heirloom that deserves to be fixed by someone that knows what he is doing.
https://store.stevesgunz.com/index.php?main_page=contact_us&zenid=k463amgafj186hbfk5p3o871l7
https://store.stevesgunz.com/index.php?main_page=contact_us&zenid=k463amgafj186hbfk5p3o871l7