There is a wire attached to that trunk light. That wire causes rattling (at least for me). You should tighten or wrap that wire.

And you can take that panel off. Its quite easy and straight forward. Let me know if you have any questions.

Either something inside that plastic, possibly loose clip. Sounds like slight metal on metal rattle. Did you see if maybe the license plate shakes when you rev?

got it all figured out, it was the rubber trunk liner that wraps around the base of trunk where it contacts with the lid of the trunk. Just wasn't tucked in on one spot, thanks for all the help.