Although we're wondering whether Sam's trying to scam Best Buy--though he would have had to have been thoughtful enough to save a paper from September 16th--the assistant manager accepted the return and had given him a new one, completing the return, when the manager came up and took the new one away from him and said Sam wasn't allowed to return the item.
The manager told him he'd have to take it up with Western Digital; WD told him that it was made in Malaysia on September 4th. The paper the tiles were wrapped in is the New York Post, making it highly unlikely that someone from the manufacturer tampered with the box on their end.
At first, we thought it could have been a case of open-box fraud, that is, an item that's been returned and resold, but it appears to be a case of "new" box fraud. We'll keep you posted on the outcome of this one.