After the CS-1 production run (both for Customs Service and over-run guns shipped to US distribution), the factory left this model in the "line" for future law enforcement orders. Think of the CS-3 as simply the same model as the CS-1 but a later engineering change. The basic CS-1 features are there - bead blast finish, round butt gripframe on both 3" and 4" models, and a pinned in front sight. The CS-3 also has the later - CNC machined - ejector star that appears to be a square cut (due to the CNC machining), as well - the front sight is wider - 1/8" instead of the CS-1 model's 1/10" wide blade.
Many CS-3 guns were shipped into US distribution, but the majority that I've seen were actually shipped to S&W's German distributor - Wischo - and marked on the sideplate as ".357 Security Special". These guns were 3" guns. They were apparently slow sellers and many were returned by Wischo and released into US distribution.
Here's a couple CS-3 guns, the first (3") was a Wischo gun, the second (4") was shipped to a Texas distributor. The standard front sight from the factory was a plain black ramp, I've replaced both of mine with a Patridge front blade, and both wear the requisite Spegel grips.
