They are...actually pretty neat how they did it. Don't know anything about the story line, but I think I prefer the way he looks if you put all costumed arms on him instead of the 4 bare arms he comes with, but matching the blues is a little tricky.
Yeah the reason his arms are not costumed is because he screwed up a "No-Powers" serum and four extra arms ripped out of the side of his costume. He kinda just left them there until he could figure out how to reverse this bullcrap.
although there was this "what if.."