The Express is more of an economical version which means it won't have all the insulation and tech, but it still shouldn't creak, squeak, and rattle. I'd have the dealer look at it. In the past I've used the soft side of tape style Velcro to insulate plastic from plastic and its worked great. If the dealer doesn't resolve it, try my trick. My '98 F150 with 94,000+ miles still is squeak and rattle free.
If you want a quieter truck and don't mind doing some work, tear out the interior and use a dynamat style product to quiet it down. I did this with my G8 and it made a huge difference.
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