Check out this unused premiere edition Wii version legend of Zelda Twilight princess strategy guide along with the insert and poster attached still!

While it was completely unused, the outside cover is bent up a bit probably from the poster still attached. I am guessing once the poster is removed a heavy book can lay on top of it to flatten back out the cover but somebody more experienced with books than me can take a look!

Take a look at the pictures and let me know if you have any questions!