The Missouri State Highway Patrol guns were 5" .38 Combat Masterpiece revolvers (tapered barrel) - see my post #2. 365 units were ordered and shipped in four shipments: June 13, 1952; October 3, 1952; October 15, 1952 and October 13, 1953. These were all five screw guns. Serial range was from K147000 through K157000.
The 5" K-38s have been documented above. Those were four screw units. The fifth screw was eliminated in 1956, based on a management directive in 1955. Hence, the Illinois units had only four screws.