the processor will have what it is laser etched into it for verification. you will be able to tell if its been tampered with.
If NewEgg wrote "i7-920" on a steaming pile of poop and sent it to me I would believe that I had a working CPU. That's how much faith I have in them. I have a hard time believing a company with a reputation like NewEgg would risk it by doing something so foolish. If something like this really did happen, it would almost certainly be isolated instead of systematic.