That would be great if it was possible. But I have never seen or heard of any method of dent and ding removal in gunstock wood that doesn't involve removing the old finish.
That may not be a bad thing if the stock is fairly beat up. A good job of steaming dents can work wonders, and avoid a lot of sanding. But if it isn't all that bad, or oil soaked, you may be better off to just do a light cleaning. Follow up with a light coat of tung oil sparingly rubbed in, and then a coat of Johnson's paste wax after the finish is well cured.
