This thread reminded me of the rather amusing situation regarding the Titan novel Fortune of War, in which the cover was supposed to be an image of the Titan, but somehow they mistakenly used an Akira class ship instead. It wasn't until the cover image was revealed to the general public that this mistake was noticed, at which point they just barely had time fix it. They did, and the published version had the proper Luna class Titan, though from what I hear the effort to make a new cover involved some quite literal eleventh hour type stuff.