Looks like its white paint and should buff right out.
It looks like you just need a mirror cap from the picture.
I would replace them with the OEM CF ones.
Best price I found on ebay
or you could buy these and repaint them
15 F36 435i Gran Coupe M-Sport Estoril Black Dakota Leather, ZM2, ZDA, ZDB, ZLP, ZPP, ZTP, Heated seats, HK sound MODS Gloss Black 19" 442M, ///M Performance: Rear Color Matched Diffusor, Black Grille, Gloss Black OEM Trunk Spoiler, Floor Mats & Rocker Panel Decals, Painted IND Reflectors, Black Tailpipes, 3M Bra, 20% Tint, Black COA Frame