The absolute "gold standard" public database is a physical book: The Standard Catalog of Smith & Wesson by Jim Supica and Richard Nahas. Now in its 4th edition, this book contains nearly comprehensive tables of serial numbers, production changes, and engineering variations directly transcribed from factory records. If you plan to collect S&W firearms, this book is an indispensable investment. Contact Smith & Wesson Customer Support
Many of the world's foremost S&W experts frequent these boards. If you post clear photos of your revolver—including the serial number (you can blur the last few digits if you are uncomfortable sharing it completely publicly), the markings, and the grips—members are usually more than happy to help you narrow down the production year. Where to Go From Here smith and wesson revolver serial numbers database
Does the revolver have a 4-screw sideplate? That changed to 3-screw in 1961. Your 1957 gun should have 4 screws. If it has 3, something is wrong. The absolute "gold standard" public database is a