I KNOW they are different, not sure about size though. I think they're are the same size but if one is flat and the other one is curved anyways, it shouldn't matter.
Are you sure?? Looking at closer pics of the body, the P5 is a flatter surface where the emblem sits. If anything, it's convex. On the sedan, it's concave, there's a harder crease there that makes it seem like the contours of the emblem would have to be different for it to look and attach properly.