Well, as the thread started, these are marketed as "accurate" ears. The MS1 and SgtFang ears (identical) are similar in a lot of ways to these ears, but from my perspective, are miles apart.
I don't mean this as a "let's drag the MS1/Fang ears through the mud session" but merely a quick snapshot of why these ears can stand to be upgraded to a more accurate PP2 origin.
The MS1/Fang left ear is most similar yet it is shorter by a mm or two. The right lower ear is not as wide by a mm or three. Of course the MS1/Fang right upper ear pieces are shorter and narrower, but Tyler Durden already addressed that. And it's also obvious that BM tried to address that in his helmet as well. Yet in other cases the MS1/Fang ears are only suffering from distortions in the cast that cause inconsistent thicknesses of some dimensions or lines that aren't exactly straight – along with rounded corners where there shouldn't be. Not to mention the MS1/Fang un-even three-hole signature.
But if I've observed anything with these pieces, it is how much difference a millimeter can make.