Howdy
Prior to 1968, it was not a requirement for firearms to have a serial number. I have a couple of old Stevens shotguns that have no serial number on them. However, most firearms manufacturers, particularly manufacturers of quality firearms, such as Colt, Smith and Wesson, Remington, Marlin, and Winchester, to name a few, stamped serial numbers on their firearms from the beginning. After the Gun Control Act of 1968, all firearms manufactured in the United States, MUST have a serial number.
Smith and Wesson is no exception. Smith and Wesson ALWAYS stamped a serial number on their firearms. Going back to the Volcanic magazine pistols, the SN may have been hidden inside. But after 1857, with the beginning of the modern Smith and Wesson company, all Smith and Wesson products have always had a serial number stamped on them that was visible without disassembling them.
This is the oldest S&W in my collection, a No 1 Tip Up 1st Issue, 5th Type. It left the factory in 1859.
In this photo I have taken the liberty of blocking the last two digits of the serial number.
During the Top Break era, S&W stamped serial numbers in 4 separate locations. The bottom of the butt, the rear of the cylinder, the underside of the barrel latch, and the top strap extension on the barrel.
This New Model Number Three does not belong to me, it used to belong to a fellow CAS shooter. I have blocked the last digit of this SN.
This NM#3 belongs to me. I have blocked the last couple of digits of the SN, but it can be seen on the rear of the cylinder, underside of the latch, and near the latch on the top strap of the barrel. The SN on the underside of the butt was the Serial Number of record. The other three allowed the buyer to determine that those parts left the factory with that gun.
When the Hand Ejectors came along in 1896, the SN on the bottom of the butt (or frame as Bob Wright states) was still the Serial Number of record. The SN was also stamped on the underside of the barrel, or in the hollow in the barrel underlug, the rear of the cylinder, and the underside of the ejector star. This is a 38 Military and Police, Model or 1899, which left the factory in 1899.
I have blocked the last digit on the butt, but here it is.
Rear of the cylinder.
Flat on the underside of the barrel.
It is difficult to light the SN on the underside of the extractor star, but it is there, just like on any other of the pre-model number S&W revolvers.
An interesting variation of the placement of the Serial Number happened with some of the I frame Smiths. At the top of this photo is a 38 Regulation Police, at the bottom is a 32 Regulation Police.
The grip was inletted for the frame in such a way that the bottom of the grip frame was obscured.
So the grips would not have to be removed to see the SN, it was stamped on the front of the grip frame on these revolvers. This is the 32 Regulation Police.
Smith and Wesson obtained a patent for this style of grip. This is the 38 Regulation Police.
The 22/32 Bekeart models had the same arrangement.
All of the above Hand Ejectors continued to have the SN also appear on the underside of the barrel, the rear of the cylinder, and the underside of the ejector star.
Everything changed in 1957 when Smith and Wesson changed over to the model numbering system. At this time, the only place the Serial Number was marked on the gun was the bottom of the butt. Model numbers were stamped on the frame under the yoke, but the only place the SN appeared was on the bottom of the butt.
More recently, perhaps during the 1980s, Smith and Wesson also began marking the SN on the frame under the yoke in addition to the bottom of the butt. This Model 28 left the factory in 1965. I'm really not up on exactly when S&W started marking the frames like this as I do not have a lot of 'new' Smith and Wesson revolvers.
Anyway, that should answer the question about Serial Numbers on Smith and Wesson revolvers. As previously noted, it is not a crime to cover a Serial Number with a grip. It is only a crime, a Federal Crime at that, to alter or deface a Serial Number.