If a polo shirt has two men on the horse it's fake but if it has one it's real. Edit: If it's from a legit store, at a realistic price, then it's probably real. If it's off a blanket on the street or...
If you want a Ralph Lauren shirt - it says that on the tag.They have one lone horse.If you want a US Polo Assn shirt - it says that on the tag.They have two horses and men playing the game.One costs...