Brought Nikon D3100 from Amazon.com. Now worrying. If it is new or not?

It's flesh lights' glass color is slightly (~10%) yellowish… Is it okay?
I brought is last week. It's default time setting was 00/00/2010.
How to confirm that it is newly manufactured?

Sounds like you bought a used camera… Amazon sells used cameras you know. You should perhaps confirm this with Amazon. This is an excellent, up and up company that I've had excellent service and luck from. I there's a problem I'm sure they'll make it right.