How important is the halo around the barrel serial number in determining the originality of a luger? Are halos observed on all lugers or just certain models or years? Also is the vertical pin that holds the toggle pin supposed to be in the white on all models? I visited a local gun show (MN) and I could only find a couple of lugers that displayed these characteristics. I am new to this luger hobby and need all the help that you experienced collectors can give. Thanks, John