Welcome to the forums from the Wiregrass! It is a .32-20 Military & Police revolver that was likely made in the 1920's but may have been retained in inventory until 1940. These were not strong sellers for S&W and you should think twice before buying it. There are much better options for a first time S&W revolver. Ammo will be hard to find and expensive if you can find it. If you can post pictures, that will help us help you. If it is in awesome condition, and cheap, it might still be a good buy.
mid 1920's - these were sold by S&W up to about 1940, but it was a slow selling model, and most were manufactured by 1930..
I have lettered # 101xxx shipping in 1922
hopefully you re aware of the difference between a 32-20 cartridge and the more plentiful / available 32 long cartridge.
would need some clear pictures to give you a layman's view of value, - but these attract a niche market and don't bring a ton of money even though the actual production is very low (80K) for a commercial smith.
Pretty rough and in need of immediate care for the rust that's eating away. $200 would be worth it. Guy's note about ammo availability applies. That said , it's a fun cartridge- particularly if you're a reloader.