Many manufacturers use a numbering architecture that embeds manufacturing information in the serial number and it may only be the last few digits of the number are in sequential order. In other words, many serial numbers aren't completely serial in nature.
Nikon is also protective of it's manufacturing data so they won't reveal the manufacture date or plant where your camera was made.
I purchased one of the very first D7000's and my serial number started with 300xxxx.
As suggested, check the firmware version. If that's up to date it will be difficult to tell and time-consuming to find out more.
Enjoyed your new D7000, it's a great camera.
"Red is gray and yellow white, but we decide which is right ....and which is an illusion"