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
14 F15 X5 3.5i M-Sport SG Terra, Fineline Oak, Driver Pkg, Prem. Pkg, H/K, Spare, 20" 469M Rims, Park Assist, Surround View, Shades MODS Performance Black Grille & Rocker Panel Decals, Painted Reflectors, 3M Bra, Black OEM X5 Frame