I have a brass 30x155B fired Case headstamped “4-78” at 12 O’Clock, and “184-И” at 6 O’Clock. There is also a faint inspection mark that looks like “20” upside down underneath the 6 O’Clock hadstamp. This headstamp is a conventional impressed headstamp. Am I correct that this case was made by Zelenodolsk Factory Associates, Kazan Region, Former USSR? And is “4-78” a date of April 1978? What is the meaning of the “И” after “184”? I always like to double check with these Eastern-Bloc cases. Thanks in advance for your help. See photo of headstamp below: (Had to leave it big so it could be cleary seen).