I'm interested on Nikon 10.5mm f/2.8G ED AF DX Fisheye Nikkor Lens from Amazon?

Is this a USA len, or gray market?
Does it have a Nikon USA sticker on the lens body? What is the warranty?

Really it's best to ask Amazon, and to insist that what they tell you forms part of the contract of sale. Keep all paperwork and internet files of your correspondence, keep records of phone calls.

Price should tell you. And I doubt if amazon sells gray market anything.

If you are to buy it direct from Amazon, not from a reseller on Amazon, then it will be a US version. Amazon only sells US versions with full warrenties. As far as the retailers, they are required to let you know if its grey market, but some don't always do that or do it very well… Keep in mind, if it seems too good to be true, then it normally is. Also when it comes to Camera gear and lens in for sure, you get what you pay for!

Other places to look at are Hunts Photo and Video. It appears your in Calif, so you might want to check out Sammys as well.

The Fisheye lens is a very specialized lens, and that one is designed for the 1.5x crop factor of the standard nikon DSLR, like the d80, d90, d200, d300 etc. It will not work on the uper end units that are full frame. I use the Canon Fisheye on my cameras and love the look it gives, at times, but its not used too much. About as much as my fixed 14mm F2.8 wide angle. Enjoy and have fun.