I have experience restoring Winchester's and Marlins while preserving wood and metal patina and sourcing original parts that need replacing.
My work has been for myself however. Even though I don't do this professionally, my work always turns out spectacular and better than most pros that I've seen.
I'll attach a picture of a custom gun rack that I just built for my two Winchester's (hand cut cradles and laser etched labels included) and the 1894 on the bottom was just restored by me to full perfection while preserving the patina and wood furniture. It was in rough shape.
Depending on how bad the gun is, I might be able to help. I live in St Petersburg Florida.
If you want to give me a call so I can assist you... possibly help you do it yourself or do it for you, You would have to private message me and I'll give you my phone number. You can speak with me to feel me out and ask questions.
In the meantime I'll attach a photo of a 1894 Marlin I just engraved some of the wood on to customize it.
Regards,
Patrick