What the roof seam for above each of the doors?

[BrilliantBlackHemi]

On the 300C, there is a open seam between the roof and the sides, above the doors. It's got a rubber piece in there. I wonder why it's not shaped steel like the LH cars? I hope this is not a dirt/grime catcher or another rubber surface to get white FROM wax and shrink/crack with UV light exposure.

I also wonder why the pillars between the front and rear windows are not painted Gloss. I think that holds up better. I've got the flat paint on my 300M and it's been a lot of TLC to keep it in good shape (Back to Black regularly).