I've got a SIG 1911 Model TTT that's not quite perfect in terms of slide to frame alignment (actually, the slide on mine protrudes-barely-to the rear, the opposite direction from the op's). The "protrusion" is barely noticable (until you first spot it
) and the pistol functions perfectly and is very accurate. In my view, it's a minor cosmetic issue and, so long as the pistol functions correctly, I wouldn't give it a second thought.