@buttons; you may find that the OEM VW centre caps don’t fit aftermarket alloys, which would be a bit of a giveaway that they’re not OEM.
You may be able to source some non-genuine VW centre caps online, or a set of centre cap stickers with the VW emblem. However, they’re likely to be the old style VW emblem with thicker lettering, so won’t match the any other VW emblems on your car (e.g. front grille, hatch handle, steering wheel centre).
New style;
Old style;