39 holds less rounds then the 59
Standard Catalog of Smith and Wesson
Basically, nothing.
The markings.
Size.
That will depend on what are you comparing it to.
An engineering change.
In between the K and N frames. Models include the 586 and 686.
Yes. Many different models made.
Different makers. The cartridge used is the 9x19.
No tirggerguard screw is the main one.
Your serial number was used by Smith and Wesson for the models 10,12,13,45,64,65,547.It dates this serial number to the year 1979.