You can't. Sadly, all too many of these are now being found to be cheap fakes, passed of as the genuine item. It's amazing what people will do to make a dollar off the notoriety of a brand name product. That's why I never buy products backed by the famous or in this case the infamous. There's just too much hype to their marketing practices.
There might be fine print but don't bother getting some they could be fakes and they're are not the best I gaurantee you will find a better pair for cheaper then 300$ and I think buying from a known retailer would be better then some guy in alley