If the UPC is gone, (namely, the box has been cut and cardboard is missing)I would suggest it was sent in for rebate as mentioned. I would ask the seller that very question.
If there is no UPC to start with, cardboard all intact, I would suspect a Chinese knock off. I would ask the seller to provide a sales receipt from a Canadian Store.
Depending on the answer to the above question asked, i would make my decision to buy or pass