Look for random extra fasteners. I seem to find them on a regular basis from the factory. I find pieces of zip ties as well. Also, some of the stock wiring could be tied down better which can help eliminate some rattling. Good point on the airbag fasteners, remove the parts stuck in the dash right away. It is also a good idea to not screw in the replacements until you go to snap it in place as letting them rest against the dash can bend them and make it hard to line up with the holes if you leave them in the cover overnight and let it all dangle.