Rattles and squeaks are seriously maddening. When I buy a car now, that's one of the highest priority items I check on the test drive; find a rough road and listen for noises. Of course the rattles increase over time as parts loosen up. I suggest biting the bullet and see if a wedge or shim made out of cardboard or paper or rubber "fixes" it.
I had a '90s Ford T-Bird that I put little cardboard and paper and rubber wedges and shims in the dash, door panel, a-pillars, etc. to stop buzzes and rattles. The interior plastic on that car was awful. My Mustang is a lot tighter, but in cold weather something in my instrument panel buzzes.
2011 Kona Blue GT Premium