Yeah, it's already been known that they're both similar, and that the last book cover was inspired by the Rolling Stones. I believe it's David B. Mattingly who is the fan though because K.A. never actually gave any ideas for the book covers. The marketing people would just take the brief plot outlines that she would make months in advance and then plan the cover based on it (in most cases it was whatever new morph they would be acquiring in that book). Same thing goes for the titles for every Animorph book. K.A. never actually named any of them, it was the marketing team behind Animorphs that did that.