Both guns have the same wide aluminum trigger. The GCT Stainless has a modified grip safety (not "as issued" style) and a skeletonized "enhanced" style hammer. Both are not allowed in the service pistol phase of CMP competition. The rubber wrap-around stocks, available on both pistols, are also illegal for service pistol. The newer NMs have wood stocks. The idea in CMP (military-type service pistol, like the distinguished match and the President's Hundred) is to have the pistol closely simulate an issued pistol. Gun can be accurized with adjustable sights, but no target stocks or after-market type additions like beavertails or cool hammers, etc. Trigger must not be less than 4 lbs. The blued NM meets these requirements. The GCT is legal for the standard .45 caliber phase of the NRA 2700 course, though. Both are pretty close to being competitive "out of the box" (for bullseye competition), with the addition of a TIGHT bushing, trigger job and a good muzzle crown. Excellent pistolas.
Bob