From that I can see my secondhand D3 is Japanese. Is this likely to cause me a problem? Is there any real difference apart from the serial number? Don'tr mean to hijack the thread but think this is relevant.

http://www.flickr.com/groups/d600club/discuss/72157632004966262/
Serial numbers beginning with:
2 - Japan
3 - USA
4 - Europe (excluding UK)
5 - Canada
6 - Australia / New Zealand(?)
7 - Asia (excluding Japan)
8 - UK
Heard that EU & UK might now be the same though?
so presumably more important to use the prefix #'s to identify regions.