I've seen the Ebay auction and its pics, there are a lot of details: pics from afar are clearly photoshopped/tweaked to make it seem the paint app is good as the original. The closeup pics revealed that the Cerebro helmet has nowhere near the smooth/slightly reflective application of the original, it's dull, flat grey with paint bleeds. His left thumb, the one attached to Cerebro, didn't fit in the hand properly, you could clearly see the seam... I mean, it was disaligned from his hand. Also, in these closeup pics, the background is a little blurry but you could tell that the face had nowhere the detailed paint application of the original.
Basically, only someone who has no clue of how the original looks like could fall for it and mistake it for the real one. Not saying it wouldn't happen because I've seen people falling for stuff that was obviously fake (i.e. the Hulk vs Spidey diorama, the recast looks painted with crayons).