Yeah I'm believing this is fake. Serebii or no other site states this as an official leak and usually we don't get leaks till around the 14th or 15th.(Also we usually get a full photo of the pages when leaked.) Plus the protagonist's artwork seems odd and off to me. It doesn't really seem like Sugimori's style much. I mean sort of, but it feels odd if he would draw the character like that cause it looks disproportional.