Serial numbers for lenses are world-wide, but for some models there is a separate series for Nikon USA. I'm not sure why some models get USA serial numbers and others don't, it seems rather random to me. For example there does not appear to be US serial numbers for the AFS 20/1.8, 24/1.8 and 35/1.8, but there is for the AFS 28/1.8 and 50/1.8.
Serial numbers for Nikon cameras are regional (Japan, USA, Europe ...) except for most "pro" models.
For the Nikon 1 system, there are series by region and by color - too many combination, and too little data for me to track accurately so I gave up on them (besides there was little interest from me and not much demand from the general public)
Regarding the 28-300, I have seen nothing to suggest there are sub-series within the USA or World serial numbers. If there was a small gap of a few thousand, my data wouldn't pick it up since I don't generally get more than one serial number in thousands, so it could be possible. My feeling is that serial numbers are more or less continuous, and numbers are only reset for major changes such as shifting production from Japan to China. There may be minor silent changes along the way as the assembly line is refined, or cheaper/improved parts are used, which could mean lenses made later perform differently from earlier examples.