I was an IL state police trooper (in uniform) from 1968-93. I was issued a Model 39 (no dash) in the academy. I bought it back around 1980 when it was replaced by the 439 (Model 39 inventory #is 415). In the very late '80s or very early '90s, I was issued a 5904 to replace the 439. Between 1968-early 1993, we had 8 different 9 mm rounds, as detailed above by ISPcapt.