Black out pieces for rear bumper?

Ok, this is talking about parts, but not really tech. Im confused so mods move it if you want (obviously!). Anyway, I wanna get a chin spoiler for my GT (like the Mach 1) however If i do something on the front i have to do it to the back (a little OCD kickin in, it has to be symmetric!!) and Ive seen some black out pieces for the rear bumper (and rear trunk lid? in between the taillights ) and i wanna know...is that a factory option, can i get them (aftermarket) and if so how is the quality and ease of install (drilling?) Oh well, just wondering...

hey, thanks man! the only other thing is the other piece im looking for is the black piece that, if you look on the picture, covers up the indent below the "grill" on the back bumper...if im not explaining it right ask again and i will try another description