Ok so this is going to sound really dumb (sorry, it is dumb), but I got Radion XR30 Pro and RMS tank mounting kit. Both were "open box" at BRS and instruction booklet is missing. And it's fine because I eventually figured it out on my own. Except - eyelets included with the light itself. (The mount came with regular screws.) The eyelets with the light itself look more serious. But - there is an eyelet screw and a nut. I can't figure out what the point of the nut is. Is it necessary? It doesn't seem to go on the other side of the mount. The eyelet I think can just go through the mount into the light... do I need this nut???