I have a rifle with" fish hook" style sling swivels that are on a rifle that is over 60 years old. Can anyone give me the history of this style? I was told they are Winchester made and another says they are Savage style. They appear to be of a hardened spring steel and are sharply tapered to a point that passes through the eyelet style stud on the forearm and toe of the stock and fit a 1 inch sling.