I think that Harry is the Heir of Gryffindor because when he first got his wand,it shot out red and gold sparks. Also, he was the one who pulled Godric's sword out of the sorting hat, Godric and Salazar were enemies so the Heir of Slytherin has to face the Heir of Gryffindor(which is Harry), his birthday is July 31st which in astrology is the sign of the lion and his birthstone is ruby which was found on the sword.