I just received a Mint 1960 Parker 51 with a flat conical barrel. I read in the Parker 51 book that the Mark II version is somewhat shorter than the regular, but I am not sure if what I got was a demi or a regular version. Any suggestions on how to tell? The book says the Mark II is a little thinner and a little shorter, but just how much of a difference should I see?

Thanks!

Well here is Richard Binder's "51" page if it helps at all

http://www.richardspens.com/ref_info/51_profile.htm

Thank you for the post. Richard Binders section was very helpful!