It's the BMW lettering that Reps don't seem to have. The Reps on my car didn't have that but they were exactly the same sizes and offsets.
If you are shelling out for genuine ones make sure they really are CSLs. CS wheels look the same but the fronts are only 8J not 8.5J. Rears are the same for both.
Or you could save a few thousand and buy Reps given how often you change your Zs. :lol: