I'd like to know this as well. I see lots of views on this thread but no replys.
So, I need to look at a Grand Touring or Signature a little closer, but I imagine you'd be able to buy the chrome trim from the dealer. I'm honestly surprised no one has done this already.
The only flaw would be if these chrome strips "snap" into place, then that would require the entire plastic piece to be purchased along with the chrome. Of course, one could remove the tabs with a dremel and then use mounting tape. This is all assumption until more research is done.