Smith and Wesson began listing serial numbers in 1984 with a three letter prefix to there serial numbers.So you should be able to identify the year of manufacture by the 3 letter prefix and then the following number.Smith and Wesson began production of the model 4046 in 1991,and discontinued this model in 1999.The Smith and Wesson model 4046 Tactical was made from 2000-2002.I hope you find this of interest.
It is a J frame.
Compare it to known examples.
Find a copy of the Standard Catalog of Smith and Wesson, sn data is in it.
Check the butt and crane area of the frame.
The model 65 is built on the K frame.
Open the cylinder and look at the frame that is usually hidden by the crane. The serial number is stamped on the frame.
If its a 5 shot its most likely a J frame. If its a 6 shot its most likely a K frame.
The Model 13 is built on the K frame regardless of the N marking.
Normally stamped on the left side of the frame for autos, and on the butt for revolvers.
Standard Catalog of Smith and Wesson, 3rd ed.
Look on frame inside the cylinder area to find the model number of a Smith and Wesson 357 mag snub 2 in stainless barrel