Earlier this week, Jeff Kaplan announced that Competitive Mode would have exclusive rewards such as a "golden Reinhardt Hammer" and other golden weapon skins, introducing a new type of cosmetic. These images are taken from the Korean PTR (source at bottom). The Reinhardt Hammer depicted above indicates that these indeed might be the new weapon skins that we will see in game.
Like all PTR assets, these may not be final and are subject to any change.
More info: http://m.inven.co.kr/board/powerbbs.php?come_idx=4677l=99