In the first pic, right where you are pointing, if that's what the door surround fits into when it's installed, then I know what part you're talking about. Mine has that piece on it & it looks like a factory part to me.
I don't know what it's called, but Quadratec, 4wd, and the dealers should have them. If you're looking to get it cheaper, then check with some of the online salvage yards. www.collinsbrosjeep.com is one.
His: 1999 Flame Red TJ, With a few mods...
Hers: 1987 Grand Wagoneer, stock w/Falken Wildpeak ATs