Sorry, the every fifth was an approx that was more of a feeling. My point is that I have been told that not all grips are categorically marked.
If I may quote part of what Jan Still wrote on his forum (further information on his forum):
</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Erfurt grips are always serial numbered.
Imperial DWM grips are not always numbered.
Mauser grips are not always numbered.
Simson grips appear to be all or almost all numbered.</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">So, since I was relying on information from talking to several collectors last spring, this was my assumption on grip markings:
Some are marked, but many were not marked to start with.
But I could see that many collectors on the forum do not necessarily agree with this. <img border="0" title="" alt="[Eek!]" src="eek.gif" />
Ed