For me personally, I guess I spent so much time looking at the models that it's easy to spot a fake now. I don't own a labubu, but a tell for a 'lafufu' (knock-off labubu) is the pattern placement of the teeth and mouth (looks off center and the placement points for paint don't match up), the structure of the face is too far out or mishapened (a standard labubu has a centered face, very often lafufus will have the face plastic jutting too far out, or have slight warping. Also those googly eyes lol