You might ask Clark Custom.
You will want to get a rear sight assy. for a 2" gun. That will mate up nicely with the Python barrel rib. The 4" and longer barrel rear sight tang will leave an unsightly gap between it and the barrel rib.
If your barrel is the older kind with a 2 pin front sight, it will need to be re threaded. If it's the later one with 1 pin front sight, it will have the right thread pitch.
The underlug will need to be milled out some for the larger diameter ejector rod of a Smith.
Smythons are cool.