When it comes to Pelikan 400/M400, people do often ask about the differences between the original from 1950's and the original "replica" from 1980's.
Actually, there are several differences but hard to explain/to see without having both pens side by side. The following pictures show the main differences without any claim for completeness.
Hopefully, this may help some people to get certainty about when their pens have been made.
Edited by Christof Z, 27 December 2013 - 01:45 PM.