I have an old quilt I believe was pieced by my great great grandmother. There are some rust-looking spots on it and a hole in it. I choose not to change it or alter it. I like that it looks well used and loved. I couldn't possibly add anything to it that would look different than the original fabrics.
You've gotten lots of opinions and ideas. I'd give yourself time to think about it then go with your gut. It's a beautiful quilt!