Looking at the original pic the offset is stamped on the inside of the rim, but on the genuine wheels the offset is stamped on the face of the rim (3 spokes away from the valve)
On the cut away metal next to the wheel studs there is no stamping on the black ones but there is on the genuine.
If you look at Jedi-Knights pic you can see how the spigot ring sits in a genuine wheel with space for the circlip, on the black wheels there is not a step for the spigot ring to sit on.
I assume they are a lower offset as there is more of a curve on the inside of the hub part of the rim and it has the holes for merc that they use for wheel alinment
Nothing wrong with running reps to be honest but don't pay £400 for them, I wouldn't pay more than £200 knowing that they are fakes