The only reference to a presentation case for a Combat Magnum I have ever found in S&W literature is an accessories price sheet from late in 1956. It lists a presentation case for the 44 Magnum and the Combat Magnum at a price of $5.00. I believe S&W was originally going to offer the Combat Magnum with a case, but when the first 5000 sold out almost immediately, the company realized a case was unnecessary and never actually offered it with this model. The Combat Magnums sent to Pete Kuhlhoff of Argosy Magazine (K260005) and Julian Hatcher of the NRA (K260004) each have a presentation case and one revolver (K260006) that probably was an award at the Winter Matches in Tampa, FL was shipped with a case. The remainder of the cases were shipped randomly to various distributors. Many of the revolvers also have stocks that are numbered, but not necessarily to the revolver (close, but not matching). I think S&W intended to do this, but realized it wasn't necessary and then used the numbered stocks randomly. This situation with stocks is also seen with the earliest 1955 45 Target revolvers.
I wrote and article entitled, "The "Curious" Cased .357 Combat Magnums", that was published in the S&WCA Journal, Summer 2012, pp. 29-30.
Bill