The Sn is not useful for telling model differences. This guy is right, the SN is no good for telling what model it is, BUT the best way to tell a 6906 from a 6904 is whether or not the thing is blued. if the gun has a blue frame and slide, it is the 6904. if it is stainless with a silvery slide and frame, it is 6906. ps, the gun has printed on the frame RIGHT BELOW THE SERIAL NUMBER the model number of the gun.
With the serial number that you have supplied,your Smith and Wesson model 15 was made in the year 1950.
Your serial number indicates that your Smith and Wesson model 18 was made in the year 1962.
Your serial number indicates that your Smith and Wesson model 59 was made in the year 1975.
Your serial number dates your Smith and Wesson model 59 to the years 1977-1978.
Your Smith and Wesson model 19 was made in the year 1978 by the serial number that you have supplied.
Smith&Wesson model 14
No way to tell model number from just the serial number.
With the serial number that you have provided,your Smith and Wesson model 39-2 was made in 1976-1977.
With the serial number that you have provided,your Smith and Wesson model 14-4 was made in the year 1977.
Your serial number indicates that your Smith and Wesson model 39-2 was made in the year 1976.
You can not tell the model number with just the serial number.
You will need to add the model of Smith and Wesson to your serial number to get the correct year of manufacture.