2013 Fleetwood Expedition. No idea windshield type, one piece. It's a T type for lack of more knowledge gasket / molding. The center portion is suppose to fit in the channel just above the glass. The glass looks like it's seating on a seal or glue.
This gasket or molding probably isn't the seal for the glass itself, but more of a trim piece?
Nevertheless I don't what it coming off going down the freeway. It fits snug against the window but it can be pulled up with my fingers. I noticed it cleaning the window by bumping it.