I don't believe that GC is VW 502.00 approved. It meets or exceeds the VW 502.00 spec., but it is not technically 502.00 approved. Others may disagree with my take on it, but that's the way I see it.
The way VW words their owners' manuals, they could not void a powertrain warranty item, due to GC being used. My GTI owners manual says to use a 5w30 or 5w40 with VW 502.00 printed on the oil container. It also says if 5w30 or 5w40 are not available, to use an oil of the proper viscosity for the operating climate, and that said oil should have the VW 502.00 spec. printed on the container. GC passes that test.
Nowhere in the manual does it say that the oil used must be "VW 502.00 approved".