The trim piece you ask about generally will not come off without breaking the mounts.
Have you checked Chevy pricing for the part???? these are usually very inexpensive.......oddly, the ones without chrome are more expensive than those with if memory serves.
May I make an observation: A LTZ with LS wheels and hubcaps or were those exchanged first? What size engine? 1.4 or 1.8? the body parts are interchangeable so most likely not a problem. As I said just an observation....:uhh: