Solidly they are available for purchase in game. The game in question might be unpatched because I had my friend check collection on XBox360 and couldn't find this. But I have confirmed with Disney people that there won't be discs coming for the sky and texture that we already have in game.
Bottom line these discs were scrapped @soccerdude21490 and the associated sky and texture have been available in the store since launch.
^ The skydome you can change by the Sky changer. Either pressing the button or using logic to get the specific sky. The Texture you have to highlight the ground and hit the triangle (I see your on ps3) and choose the different ground. For changing trees, it only works on the specific generic fantasy terrain.You can highlight them, hit triangle, and change it to the different styles.