Quoted By:
>hurr the hats are different it's a conspiracy! WAKE UP MAREEPLE #OMG #PSYSTRIKE #POKEGATE
No, it's just gamefreak being gamefreak, and they just forgot to update his in-game sprite. In the original Red and Green, Red had a circle on his hat on the title screen and in-game. In the Japanese Blue (and by proxy, our Red and Blue) they gave him a new title screen sprite, gave him a little animation where he throws his pokeball, and made the sprite look more like the concept art by removing the circle and making the front of his hat white. They forgot to change the in-game sprite though, which still shows the circle. When they released Yellow, they finally fixed his in-game sprite.
Also, funny how you're so focused on the hat, that you never noticed that red wears a white long-sleeved jacket in-game.
