The commenter who stated that the Model 520 was replaced by the S&W Model 681 is not accurate. As 03Clyde stated earlier the 520 was never issued to the New York State Police, so instead they issued the Highway Patrolman, Model 28-2 then the Model 681. BTW - I am retired from the NYSP.
Here is my S&W Model 520, you can even see on the box that it has been marked "357 NYSP 4IN". The serial number on the RS grip does not match the revolver's serial number of
N558241.
My grip has an inked number which I can't really read and a impressed number of 680360 or 580360. Hard to tell.
520 NYSP.JPG
520 RIGHT SIDE.jpg
520.jpg