NDhunter
Experienced observer
Nikon serial numbers follow no logical numbering system. Be warned if you are trying to date them this way.
Simon:
You are correct, as earlier models began with 504xxx, and other
combinations.
Recently they do, they have had the 550xxx shipping since 2009,
or maybe earlier. I have or have owned 3, 550's and can follow the
dates.
If they do a full run of 1,000 now it seems they start with 551xxx.
Jerry