My Swiss delivery '72 CSi has the same configuration, albeit with ratty black paint on the chrome hood grilles. It had a cosmetic restoration around 1990. Chrome fender grilles are exceedingly hard to find and the chrome tends to peel off. That would be a reason to convert to black during restoration. My Italian delivery '72 CSi has chrome on the top, black on the sides. It was restored in the late 80s so who really knows, but I don't think they would have changed the color of the grills just for fun.