Brownell's ceramic stones are about right.
Remember polishing really means de-burring, NOT "like a mirror".
Most people vastly over polish parts, trying for a mirror finish.
This often ruins parts and really serves no purpose. The idea is "smooth" not shiny.
For other S&W specific tooling, that depends on the 'smith. Although I was mostly a Colt gunsmith, here's some tools I had for revolvers in general and Smith's in particular:
A set of three or four empty, de-primed, shortened cartridge cases with the heads painted bright red.
These were used to support ejectors during disassembly.
Some gunsmiths buy a "Wessinger" type tool, or use a padded vise to unscrew S&W ejector rods. I personally used a pair of modified watchmaker's end cutter pliers, and a piece of copper sheet formed to fit over the rod head to protect the knurling.
A set of home made short brass and aluminum rods used as a firing pin test device.
Drop one of the short cylinders down the upright barrel and pull the trigger. Its driven out the barrel, testing firing pin impact and operation.
Use brass or aluminum depending on the gun and how hard the impact is.
These are somewhat more a test device for auto pistols with firing pin locks to insure proper operation, but do verify firing pin action on revolvers.
A Lewis Lead Remover to get revolver barrels REALLY clean so you can inspect them.
Also a bronze chamber brush from Brownell's to clean chambers.
Paper clips and small pin stock used to trap coil mainsprings on the plunger.
An Opti-Visor magnifier in your choice of focal length.
A GOOD bench light on an adjustable arm.
A small jeweler's swivel bench vise for holding small parts.
A small watchmaker's hand held vise. These have movable pins that can hold odd-shaped parts.
Small watchmaker's needle nose pliers, and a pair of Sargent Co. parallel jaw pliers.
Swiss made needle file set. These are finer cut and better quality than American pattern.
One of the handiest tools you can have: A jeweler's "wire saw". This is a small coping saw-like frame, with saw blades that run from as fine as a hair to about where an American coping saw blade starts.
I find the 3/0 size to be the most useful, and buy the better Swiss or German high quality blades.
This has endless uses from making tiny slits to cutting out intricate shapes.
