SOmeone referred to the Model 15 as a K-38 and that's just WRONG
THe 15 & it's bro the 18 in .22 LR are the Combat Masterpieces with
plain ramp front sight standard trigger and hammer with 4" Bbl. only.
The K-series called the Target Masterpiece include
the Model 14, K-38 MOdel 16, K-32 and Model 17 K-22
they have a Patridge i.e. post front sight, Target Hammer,
Target trigger, and were built with 6" or 8 3/8" bbl. lengths.
They all have the adjustable for W&E rear sights and internally
are probably the same in terms of finish AFAIK and built on
the same K-frame platform.
I recall my first handgun, the model 18 was 38 oz. whereas a
Model 15 was listed as 35 oz, since the .38 sized charge holes
left less weight for the cylinder as well as the 18 having the same
profile/size Bbl. was the reason it was 3 oz heavier.
DIfferent flavored apples off the same tree so to speak.