This from the Serial Number research project.
MA - G-19 - January 1990 - 2nd Gen. - Philippines
MC - G-20 - July 1990 - 2nd Gen. - First G-20s
ME - G-19 - March 1990 - 2nd Gen.
MG - G-19 - March 1990 - 2nd Gen.
MK - G-19 - April 1990 - 2nd Gen.
ML - G-19 - May 1990 - 2nd gen.
Serial Number research Project
http://www.glocktalk.com/forums/show....php?t=1287557 SJ 40