I did notice, that was the presidential pack I was referring to. However, Gamestop still doesn't have it listed as a bonus on their order page for the PC so I wasn't certain if we were getting them for PC. However since Idol and Mini got codes for the preorder stuff from Gamestop I think we can safely assume that it and the Iron Rogue/Amazonia costumes are coming to PC at some point. I don't know when the Rogue/Amazonia costumes are coming but I believe that the Presidential Pack is going to be out on August 27th for purchase.
In addition to what Idol said, I preoreded a retail version of SR4 for PC and I'm getting both Queen Amazonia and Iron Rogue costumes, so yeah, they'll definitely hit the Steam store at some point