[Ron Wood]

As a general rule, early Lugers that have the serial nmber stamped on the "flange" at the rear of the barrel, as this one does, will not exhibit any halo around the numbers. On later Lugers that have the serial number stamped on the constant taper or "straight" part of the barrel, the halo effect will invariably be seen to some extent on an original finish gun. This topic came up once before, and the reason for the lack of halo on the flange is not clear, but one might guess that the numbers are more protected from wear in this recessed area, and/or there is a slighly different work hardening created during the milling of the flange radius that affects how well the blue "takes" on such a surface.