Unusual Lugers’ variations

[A.Mifsin]

Thank you Ron, if it is a rare variation I agree, but how can you say it is a factory error? For example if the barrel is replaced, who knows when it was replaced or a side plate, toggle changed. Those unusual Lugers, that we talk so much about, could they be modified after they left the factory? If there is some sort of documentation than it is understood, otherwise it is the opinion of the more experienced Collectors I think.
Alf.