All were stolen form National Guard armories.
Law enforcement officers back then were responsible for supplying their own firearms. During the 20's and 30's money was tight and the .38 Special revolver was the weapon most could afford. Usually with a six inch barrel not a snub nose revolver.
As for today, it's interesting who these police chiefs are who are arming their departments with just not military full auto weapons but also with armored assault vehicles, most are liberal "progressive police chiefs."
When I drive through the city of Monrovia, Ca. today which has a population of around 36,000 it's hard not to shake your head and breakout in a laugh when you see their black armored assault vehicle driving down a residential neighborhood with a machine gun turret on top.