Howdy
Yup, they are all prewar. I'll bet if you look in front of the trigger guard you will see another screw, defining it as a Five Screw S&W.
Officially called the 32-20 Hand Ejector Model of 1902 or later the 32-20 Hand Ejector Model of 1905. Last made in 1940. This one was made around 1920, I have not lettered it yet, so I am not sure exactly when it shipped.
S&W honored the old WCF naming convention in the caliber markings on the barrel. 32WCF (Winchester Center Fire) instead of 32-20.
32-20 was one of the old Winchester Centerfire family of cartridges, which included 44-40, 38-40, 32-20, and 25-20. Originally designed as rifle cartridges revolvers were chambered for them soon after they came on the market. In the old nomenclature, the first number stands for the caliber, the second for how many grains of Black Powder the cartridge held.
32-20 is a fine old cartridge, but you will have difficulty finding loaded ammo. Black Hills makes cowboy loads for it, which will be safe to shoot in an old revolver, as long as it is in good condition. I just checked Midway USA and they have 32-20 Ultra Max cowboy ammo in stock which would be safe to shoot in that revolver. It ain't cheap. But what is these days?
When you look for any of the old WCF ammo on line these days, sometimes you have to go to the rifle ammo section of a website rather than the handgun ammo section.
In this photo the round on the right is a 32-20, the round on the left is a 38 Special. If you look carefully you will see there is a slight bottleneck to the case.
A 32-20 Hand Ejector may not be the best idea for a casual shooter, but I am still kicking myself over one I passed up last year for $300.