I have not shot it yet, but soon hopefully. An older guy at my club told me (as did the moderator on the 1911 forum) that almost all of these pistols have the mark, because that was how the soldiers were trained. They had to be able to get the gun together in the dark or in a fox hole, so they were told to get the pistol together and not to worry about esthetics. If its a military 1911/1911A1 and it doesn't have the assembly/idiot mark, it was probably unissued.
That being said, I agree that my scratch is one of the longest I've seen. At least the mark matches the slide to the frame. The glass is always half full........