As a machinist and former employee of a cylinder head shop, no professional did that. Every valve stem would be tipped, there would be no residue in only half the cylinders, and the scotch brite scratches wouldn't be there either. Looks like it was done in someone's garage and then laid on a dirty table, only to be dragged off ruining the deck surface. On top of that, it doesn't even look like it was soda blasted.

PS....You didn't overpay. That's about market price for a set. They just don't look like what was advertised.