Help identify a S&W revolver

[wheelgun610]

I was wondering if the "N" meant nickel, and whether that was stamped at factory or by a private plating company.

It's the standard factory marking for nickel plated guns at that time. For some reason unknown to me, a few years later, they started stamping the 'N' on the right side of the grip frame. And as mentioned above, it does appear that gun has been refinished at some point, and it's definitely not factory quality refinishing.
That would hurt the collector value, but shouldn't affect the sentimental value.

 

[DARE]

S&W put the B there if the gun was blue when it left the factory. No B means the gun was originally nickel. I would say this gun left the factory as nickel and was then refinished in nickel but not by the factory.

 

[wheelgun610]

S&W put the B there if the gun was blue when it left the factory. No B means the gun was originally nickel...

As mentioned, the N on the right side of the grip frame was used to indicate a nickel finish during that time frame. Then at some point, they began placing the N on the left side. But yes, the B in the shroud or bottom of the barrel was the indicator of an original blue finish.