My skin shop

dunno why I got down voted for posting this, but just wanna know. I know the skins shop works on recently played champs, is it possible to get two skins for the same one champ, also will we be getting legacy skins? ive been playing riven and wanted the dawn bringer to be on sale, but riot stated that its an ultimate so they're not going to put it on sale, id like to know if I could get the world championship 2016 riven or dragon blade riven out of the skin shop? for those asking what a skin shop is, just wait till tomorrow and youll see when you open your client.