I have a Polish W98 rifle that instead of a serial number has "GE" where ever you normally see a complete or partial serial number on Mausers. Have had it for sixteen years and from time to time try to find out why the letters in place of a serial number. Way back, two other members said they had like rifles, but with different pairs of letters. The receiver is marked Polish Eagle/P.F.K./WARSAWA/1924. It has a "lange vizier" rear sight. The bolt is mismatched; nice and shiny, and no Polish mark. So far. no one has come up with the reason for this substitute for a serial number.. My only guess so far: a few rifles made for some special purpose and marked accordingly; i.e., were kept at various points in the factory as samples or standards, and the letters were to make it easier to ID them and keep them separate from what they were shipping out. Have you any ideas or heard something about these rifles?