Unless someone brought his own personal handgun to the Southeast Asia Tea Party I would imagine that there were no Model 10s in Soldiers' hands, not officially, anyway. All of the leather I recall from that era was designed for 1911s. But someone might disabuse me of this notion - we shall see.
Could be a USAF thing, or maybe a helo pilot thing, but I never saw revolvers in the Army.
AF did have Model 15s,
Never saw a revolver holster during SEA with a flap.
Here’s the issued one I wore.
When I was assigned to Charlie Company, 101st Aviation Battalion (Black Widows) we bought buscadero rigs "outside the gate" for our .38 SPL revolvers (belt loops in the back and all). After I was transferred to the 3rd Brigade Aviation Platoon (Thunder), I got a back injury from flying loaches with the ammo in the loops pressing against the armor plate and on my spine. The supply guy issued me a shoulder holster. I carried a 50 round box of ammo in the pocket of my chicken plate. BTW, I was issued a, brand new in the box, S&W model 10 at Camp Evans. We had FAC's with the USAF embedded with us. They flew O-2's. Their call sign was Bilk. It's been a lot of years, but I think I recall seeing them wearing the flap holsters. The jet jocks mostly wore survival vests with the black leather holster attached in a "shoulder holster position".Ok Army Guys -
Time to stand proud and talk loud.
Did you ever see any Army folks in SEA wearing a revolver holster
with a flap like in the OP?