I’ve dismantled almost all interior parts but this doesn’t resemble anything familiar. It looks like a rivet which has been broken at the root of the rivet pin. Only rivet in the interior I remember is in the Model S facelift car door card, holding the door card at upper outer corner with a piece of strap. If you have had any work done on your car where the door card needs to be completely removed, this rivet has to be broken and replaced. I’ve been able to do what’s needed without completely removing the door card, so did not remove the rivet.