How to check if a Macbook Air is original?

Hello, I like Apple products a lot but sadly I have not been able to buy any Apple product except iPod Touch. I always wanted to buy a MacBook but have not been able to but now I may be able to buy a MacBook Air after a month or so.

My question to the comunity is How can I check if a MacBook Air is a original or not? You may find a question too childish or funny, but the fact is we dont have any Apple Store in my country, I will have to buy it from 3rd party vendor. I am sad and ashamed to say that in my country they sell a lot of fake or duplicate products. So I was asking if there was any way if I can check without openning the box the MacBook Air is original or not? (For example in HP Printer Cartidges, there is a serial number ad we can sms it/or use website to check if its original or not)

It would be of great help if any one tells me how to check it. Thanks in advance.