Thought I'd seen it all. Even a nice Merkel in-the-white with no markings that was described to me as a lunch box model. :)
Has anyone else seen one of these? He wants the slot cut and hole drilled and tapped for screw.
Going to have to ask him if it's been heat treated, I reckon.
(https://i.ibb.co/btsVJCp/rawmauser.jpg) (https://ibb.co/btsVJCp)