It's a very late .32 Double Action Fifth Model made from 1909-1919 in a serial range of 283,000 to 327,641.
Looks to be in nice shape. Neat little pocket gun to have in the family!!
Tony,
Yours is one of the last .32 DA w/hammer top-breaks made by S&W. They did continue to make a Hammerless version
(aka .32 Safety Hammerless, New Departure or Lemonsqueezer) up until around 1937.
The last of the .38 Hammer Top-Breaks were made until 1920 and the .38 Hammerless until 1940