Great post, Forester! Also, note:
7. Prior to the stamping of model numbers, there were only assembly numbers stamped in the yoke area in front of the cylinder. These are NOT serial numbers and won't ID the gun.
8. S&W revolvers made before WWII use up to 6 numbers for the serial. During WWII, they used V or SV for the .38 S&W Special and .38 K-200 Victory revolvers. After WWII K, S, C, D, J and N prefixes began. Some later models have the letter mixed in with the numbers. After mid-80s, SNs begin with 3 letters, followed by 4 numbers.