I got the old gun - officially Merkel Suhl (8x57IR - 16/65). According to stamps, the first proof was between 1912-1939 and the second at March 1955, probably (NDR)? According to form the word "Nitro", it was impletented in Zella Mehllis, but I dont know if it is the first or the second proof. There is not complete inscription on the top barrel: M-----J.B/Suhl (due the placement riflescope montage). There is one Kersten lock. Is it possible it is Merkel Suhl? The serial number is quite low 15xx. I cant read the stamp on the block over and under the "crown with N" and "U" - it looks like letters HK or something that and on the second side are two stamps probably of the proofing house. Here are some photos:

I will be very happy for your response

Matesar