Howdy
Let's get our definitions straight.
The K-38 Target Masterpiece was introduced in 1946, right after the end of WWII. It was a K frame 38 Special revolver with the micrometer click adjustable rear sight. K-38 Target Masterpieces had 6" barrels.
Here are a couple. The one at the top of the photo with the fake stag grips left the factory in 1957. It is a 3 screw Smith. Also, somebody reshaped the front sight from it's original Patridge shape. The one below left the factory in 1950. It is a 5 screw Smith with the original Magna grips and the front sight has not been reshaped. Note both of them have short throw 'speed hammer' that was being used at the time. I have had these a long time, they each cost around $500 when I bought them.
The K-38 Masterpiece became the Model 14 in 1957. This Model 14-3 left the factory in 1974. I got it for a steal at $500 a few years ago. Don't expect to find one at that price.
This is a 38 Combat Masterpiece. The definition of a Combat Masterpiece means it has a 4" barrel and a Baughman front sight. They were called Combat Masterpieces because the idea was they could be drawn quickly from a holster with the 4" barrel, and the Baughman front side would not snag on a leather holster the way the Patridge front sight might. This 38 Combat Masterpiece shipped in 1953 and I paid $750 for it a couple of years ago.
The K-38 Combat Masterpiece became the Model 15 in 1957. I do not have one to post a photo of. Most Model 15s had a 4" barrel, a few had different barrel lengths.
This is a K-22 Combat Masterpiece that left the factory in 1953. Notice the similarity to the K-38 Combat Masterpiece pictured above. The same 4" barrel, the same Baughman front sight. Other than being a 22, the only other difference between this revolver and the K-38 Combat Masterpiece above is the hammer. This hammer is a typical short throw hammer with a longer than usual hammer spur.