Basically, nothing.
39 holds less rounds then the 59
The markings.
Size.
That will depend on what are you comparing it to.
An engineering change.
No tirggerguard screw is the main one.
Different makers. The cartridge used is the 9x19.
One is blue and one is stainless steel
908 - Black finish 3914 - Blue finish
The one screw basically.
52-1, single action only.
The main difference is that the TSW slide and frame were made as a matched set and have the same assembly number on each.