They were designed as 'hammerless' so that they have less chance to catch or snag on clothing when being drawn from concealment.
1910
10-100
Turn of the century or thereabout.
There have been a number of "hammerless" revolvers made, ranging from the tiny Baby Hammerless .22, thru the Iver Johnson and US Revolver Hammerless topbreaks, and includinurrent day Smoth & Wesson revolvers. All DO have hammers that are internal to the handgun frame.
10-100 usd
No published sn data. @ turn of the century
No published sn data. Turn of the century, inexpensive
1888-1937
Look under Iver Johnson Arms and Cycle Company. Their hammerless revolver was sold under several trade names, including US Revolver Co. You can probably find one for sale on one of the online auction sites.
No published sn data.
10-100
Call S&W and they will tell you when it left the factory.