Nice doing Dad, thanks. Troepolskaja recognizes МПЗ (#19304), but not 3AB. What does it stand for. 3 for "Завод" but the rest. AB?
Information about Frolov and Ushatov is correct.
AG2012 wrote:The assayer MK was Mihail Karinsky PL 1165 and 1166.
In office 1825 - 1838.
Qrt.S wrote:In addition, most likely the customs brought it there. In other words an imported object.