Hello, David:
Santa should be there today. Did you leave cookies? Haha.
Romano has seen the Armisports for a long time and can tell you if yours is early, middle or current production from subtle characteristics such as parts hardness (or lack thereof), chambering work, rifling twist, etc. If no one here can provide SN info, it will be his "eye" that tells in generalities.
All the best,
Kevin