Texasbdog,
AS you have likely figured out by now, Franz Kettner mostly marketed other maker's guns rather than making them "in house". Many of the guns marked Kettner but made by someone else may have a "house mark" of the actual maker somewhere on the gun, though not all of them. This is why it is important that clear photos of all markings should be posted. Even if the actual maker can't be identified, proof marks can provide other important information.
Mike