Well, we know Harry is a descendant of the Peverells, I.E. he is a rightful possessor of the Invisibility Cloak, so that is something. As for being a descendant of Godric Gryffindor, though...I don't know. I mean, if you use Harry pulling the Sword out of the hat, and out of the lake, you could also use Neville as an example as well. Neville pulled the Sword out of the hat as well, when he killed Nagini during the battle. So I think that puts that into perspective, as well...It's something to think about.