If trim panel means that puny litttle spoiler, it is held on by 2-sided tape & 4 bolts---ergo, there will be 4 holes left behind when you unbolt it & pry it off---which takes a lot of careful prying with a putty knife.
A decklid on a Kona Blue looks awesome I have that! It looks ugly without trust me! I think the back area covered by the decklid is too rounded in... compare it to a stang that doesn't have it and youll know what I mean.
I think the issue you will run into is that the panel from Ford also includes the round faux gas cap as part of it, so you will be missing that piece and I think that will leave some holes in your trunk lid. I have a 2010 that came without the trim. If you're serious about taking off that panel, I'd be happy to trade you my non-panel GT rear faux cap in exchange for yours with the panel, it is a look I want for my car, and won't leave yours with holes.
Rob