Well, the prior Marvel Legos for the Avengers were only semi-accurate. They have the basic concepts and ideas right but the details can get a little fuzzy. For example the Lego Quinjet is recognizable for what it is but lacks the specifics of the movie (such as a multiple person cockpit, rotars in the wings, color, etc.). The Shield truck was the same way. Additionally, Lego Captain America had a motorcycle, which was obviously absent from the film.
So, I'd take some of the designs with a grain of salt. However, Pepper in the armor is most likely a plot point passed down from the studio, not Lego taking liberties. So, the final battle between Mandarin and Tony may include some kind of vehicle, but the actual shape may not be representative of the Lego. Also, the coloring tends to be a little off (Shield Grey became Blue).
