Actually, Model, he specified 20's and beyond.............the period I addressed was during the very last stages of revolver carry as a normal/regular thing....far as packing a .32 goes I used to regularly carry a 1903 .32 auto, back up gun.........likely the very best of the Colt autos......flat, concealable and doggone accurate. Duty wise tho, the singular one was the mentioned item, heck, given some of the .380's common for off duty wear now it truly wasn't that bad!
Don't know about others, but I learned a heck of a lot from some of those old timers (I know, now I IS one), from basic marksmanship to just how to work a case to my best advantage. Fella that taught me the most was a medical school dropout (ran out of money) from the 20's, wound up in Fla. when the '26 hurricane hit....was a deputy sheriff & one of the very first Florida Hwy Patrolman when that force was formed. God, the stories that guy could tell. Carried a nickled 19, used to tell about the closest call he ever had was by a fella from a turpentine camp with a Colt .32-20..........Florida was truly a frontier State back then and some of the tales would make for a good book.
Don't ever sell those old timers short...they did a hulluva job with little to work with other than their wits and good common sense. Formal education was a rare commodity in the field back then, but more than made up for by some really class act folks.