It is my understanding that Nikon will sell parts to 3rd party shops as long as they are authorized Nikon repair shops. Have I got it wrong?
And yes, check your invoice, if B&H sold you a gray market lens, your invoice will clearly say so.
The issue is not the warranty, which, as pointed out, is not transferable. The potential problem is the difficulty of getting repairs. Nikon will not repair a gray market lens at their service centers, but a 3rd party shop will.