To any of you that bought the OEM crossbars and installed yourself, do you remember whether there was any separate hardware in the box aside from the allen wrench? I'd like to buy an open box offer, and they say it includes two bars, the quick guide, and the allen wrench. I asked the seller if it comes with any other necessary hardware, but haven't heard back yet. Just trying to figure out if any screws come already attached to the bars and therefore wouldn't be a concern. Thanks!