The National Match 38 special wad cutter pistols are not Gold Cups. The Gold Cup National Match name came later....
Most Colt National Match pistols (blue carbon steel) were chambered in 45acp. The 38spl models are reasonably rare and somewhat desirable as a collectors item. There are just too many better autos out there to make them a competitor. Colt NM pistols then transitioned into the Gold Cup National Match, then the Trophy model.
Getting on the stainless steel bandwagon that S&W started was in my opinion a mistake by Colt, but people want and demand crazy ideas and manufacturers respond. Hence, the Pontiac #####, stainless Pythons, stainless GCNM autos and the new S&W 66. Ugh!