I could probably snap a few pictures but it wouldn't really help in determining it I don't think. I mean I've been collecting Gamecube for a long time and this inserts quality looks to be just as high as the other GC games I have, it's just on thicker paper. Idk...but i'll add a few pics.
Well, I thought that the overall look and fit might help determine authenticity. I just went through my GC games and they are all the same thickness, that's about all the help I can offer...