It is common to mistake "assembly numbers" for the official serial number. On an S&W revolver, the official serial number is always located on the bottom of the grip frame (butt) Smith & Wesson : You may need to remove wrap-around grips to see it. Alpha Prefixes

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 most comprehensive "database" used by experts is the by Jim Supica and Richard Nahas.

Include any letters (prefixes or suffixes) as they are part of the unique identifier. 2. Consult the "Bible" of S&W (Standard Catalog)

The revolver is a 1961-production Model 19 no-dash (or 19-1), verified by both reference database and factory letter.

This article serves as your comprehensive roadmap to understanding, accessing, and utilizing serial number databases to date and authenticate your S&W revolver.