krauseb:
Without a photograph we have to do a lot of speculating. Smith & Wesson only made one hammerless revolver chambered in .38 S&W. It was called the Safety Hammerless or New Departure model. Points of identification would be.
Top-break design, with 5-shot cylinder chambered in .38 S&W.
Inclosed hammer, with a grip safety mounted on the back of the handle (has to be squeezed before you can pull the trigger).
Round butt, with black hard-rubber stocks. Checkered walnut or pearl were optional.
Full blue, or nickel plate with a blued trigger guard and barrel latch. Triggers were color casehardened.
Barrel lengths of 3 1/4, 4, 5 and 6 inches were standard (measured from the front cylinder face to the end of the muzzle). Other lengths between 1 1/4 to 6 inches could be had, but only by special order.
Copies made by others are frequently encountered, but they don't have the grip safety.
Most original 2-inch barrels have patent dates stamped on the side of the barrel, and the stamping, *38 S&W Ctg.* will be centered. Longer barrels that have been cut will have what's left of the patent dates stamped on top of the barrel rib, and the "Ctg." stamp will be off-center.
Hopefully you will find this to be useful.