You should really post your question in the Antiques area of the forum. It does not appear to be an S&W, so help here may be limited. It's probably an Iver Johnson top break revolver, chambered in .38 S&W caliber, which is a little difficult to find. The grips appear to be identified as U.S., which is the U. S. Revolver Company, whose revolvers were made by Iver Johnson. There were literally millions of this type made by different manufacturers, from the late 19th century until WWII. They are common and have little collector value, other than as shooters.