Smith and Wesson is KNOWN for making all kinds of special runs, special orders etc.
This have been the case for MANY years.
Many, very many gunshop owners , FFL dealers and just gun buying public CAN NOT tell the difference.
I will never forget walking into a gunshop once , and have owner showing me a 686 revolver with three inch barrel.
He said ," I just got it in, NIB, nice 2 1/2 inch revolver, too bad it would be worth more if someone did not worked on it " The revolver had mat finish, black rear sight blade and a THREE not a 2 1/2 inch barrel.
I bought it for 625.00 total that day. Thats how I got my second CS-1.