The two letters after the serial number on Miroku/Browning guns denote its age. M: - 0 N: - 9 P: - 8 R: - 7 T: - 6  V: - 5 W: - 4 X: - 3 Y: - 2 Z: - 1 Therefore a 2019 gun would be marked ZN and so on. I found this in a long buried post from 2003 on PW. Which in my case pre dates the internet.(Marvelous tool the search button). Thank you to the original poster. I thought it might be useful to repost it.