They are legit. In fact, his #10 is the variant and had a smaller print run than 500.
They are something else Steve (Evil Ash) brought to our attention awhile back. He even sold some here to lots of other boardies. If memory serves me right he was charging about $180 back them, but I don't remember.
I searched the internet and made a friend in Serbia to get mine. They are pretty rare.
HA! I think the seller was checking this site, cause the #10 just changed to the regular version. It's NOT the black & white variant anymore.