There are no 'exotic' handguns on display - no USMC Colts and Smith & Wessons - just a couple of the common ones of the era.
The 'gun wielder' has a Harrington & Richardson solid-frame, and they were known to use half-round-half-octagon barrels.
They never changed their cylinder pin catch - and you still see it on their old 'Sportsman' revolvers, as you do in this photo.
You pressed the bottom of the catch in - pulled out the cylinder pin and used it to clear the cylinder.
The one lying on the ground looks to be an Iver Johnson 'Owl Head' - the 'tall' frame gives it away - and most likely is in .38 S&W, since the frame size 'and' hammer did differ from the little .32 in the color photo.
Vaya,
Scouts Out!