All true.The thread is about post-WWII, and they were the first post-war Masterpiece line plus totally different than the pre-war K22, K32, and K38 Masterpiece line. Also, I use Jim Supica's and Roy Jinks" terminology for K22, since the model was a K frame, had a "K" serial number, plus the name is used by these experts in their books. They are the current readily accessible resources on the subject. Standard Catalog of Smith & Wesson and 125 Years of Smith & Wesson
BUT:
S&W's practice was quite different. The catalogs, All Model Circulars and box labels never applied the "K-22" or "K-38" nomenclature to the Combat versions. It was just .22 Combat Masterpiece or .38 Combat Masterpiece, sometimes even without the caliber.
The sole exception that I'm aware of was the spec sheet included in the box for the Model 15, after model numbers started showing up. That spec sheet did refer to the Model 15 as a K-38 Combat Masterpiece. But the box label during the same period did not. So the overall preponderance of evidence is that K-38 was not used by Smith & Wesson to describe the Combat versions in the Masterpiece line.