If you have not already done so look carefully at the top flat from just behind the rear sight and back. Generally this is the area where the maker would have signed the gun. It could be a stamp, signature, or just some letters. Also, is there anything stamped on the lock? Another place to look is on the bottom flat since some barrel makers signed their work in this position. These marks can be very difficult to see, especially the top flat so look carefully with strong light. Best Regards, Jack