As a new member, and longtime kettle fan, I believe that it's ok to get the metal round , polish legs, and make a grill look as good as it can , except to apply paint. One of my other hobbies is old bikes where the value goes down when the spray can comes out, But I never bought a kettle to fix it up and sell it . The big difference between an old bike and an old kettle is that a kettle is porcelain not paint. These things are as old as I am, and even the really clean ones have small battle scars and stories to tell. If your lucky enough to have one that you kept for a long time ,you know what I'm talking about.
You can always touch it up with paint, but once you do ,you can't unring that bell