I have one of these with a 3" barrel, and it is a sweet shooter.
Okay, let me say up front I've never shot an NCOWS match, my only experience with Cowboy Shooting is SASS. That being said, I like looking at the discussion boards for all permutations of what could be, even with a stretch, classified as CAS for interesting topics, and this is one!
The Colt Lightning is a great gun. It points well, it's DA trigger is not bad, and in spite of its smaller frame, it's more of a "DA Peacemaker" than the 1878 is, in my opinion.
I use my 3" one as a pocket pistol at SASS sidematches, and no one has ever tried to tell me that I can't. (In spite of some online arguments about its suitability for that role) I have also shot an entire match with it. This was at what was called an "Iron Cowboy" match where you needed 4 pistols and 2 rifles. I fired it, and my 1878, SA mode and didn't have even the slightest glitch. Accuracy was... not the best, but I did okay.
I know of another one at a local shop with a 5.5" barrel, that has had all of its springs replaced with modern ones. I am very seriously consideining purchasing it to go with my factgory conversion '58 Remmingon that is also a .38.
And yes, I have use low power smokelss loads in the gun to no ill effects. In fact, my loading with smokeless is noticalby less stout than black powder ones.