:idea: I am posting this as a few might find it interesting. I have a Prototype early Luger that is a outstanding piece, never been offered for public sale. Problem , no hard paper trail to prove originality. In studing the gun i noticed the bbl. dies used to serial number (magnified) had flawed 0''s. prototype lugers have a 100 prefix serial number. I began checking around, though rare, other prototypes do exist. I have found another example with the flawed 0''s. My thoughts now as I continue to collect evidence to support that my gun is valid, is why has no-one done studies on die stamps..They are the finger prints to guns. none are perfect and in many cases the comparing of die stamps could be of great interest in cases like mine..If I was younger ,I would take a crack at doing it...thoughts welcome...