Agree with Brian.I read somewhere that those with starting with 5's were not intended to be sold in the states but Canada/outside US.It's very possible some were rechanneled here for US consumption for whatever reason.Right or wrong it's anybody's guess.
Copyright © Nikonians 2000, 2013
All Rights Reserved
Nikonians®, NikoScope® and NikoniansAcademy™ are trademarks owned by Nikonians.org.
Nikon®, Nikonos® and Nikkor® are registered trademarks of Nikon Corporation.