On second thought, I decided that the numbers must be a carryover to the early Citoris from a (the?) system used by Miroku on the Miroku-marked guns or the guns they made for Charles Daly before FN and Miroku bought out Browning in '77 iirc.
Anyway, I was wrong. According to Wisner's, Miroku used a *- system similar to Browning's.
http://www.wisnersinc.com/additional...kusprings.html
Nuts.