Hmm.. I can't believe that I never noticed this, but I just looked at a picture and you're right. It looks similar, but the heart of the nobody logo is incomplete. I'm guessing that suggests the fact that they lack hearts or maybe they do retain part of the heart. Lol.. that might explain why some of the Org. seem to show emotion, depite supposedly being emotionless.
Honestly, I think what Yen Sid told Sora was what Mickey had told him (who was originally told this by DiZ). DiZ really didn't like the nobodies (because of the apprentices done to him), so he told Mickey that to make them appear more evil than they really were.. plus he was probably biased. When, in all truth, nobodies had some of their heart. Honestly, they have to at east have a piece of it, if they are going to show emotions.. unless.. some emotions can be tied to the Body and Soul. Ehh.. that's my idea of what I've heard.
(It's been said that the reason why Yen Sid told Sora that nobodies supposedly have no hearts or emotions is because Mickey told him that and before that, DiZ told Mickey, that and DiZ was biased/ hated the Organization a a whole.)
Anyways, do you think that part of the heart being in the nobody logo might relate to them having at least a little part of their heart? I mean, sure they can probably fake their emotions, but not every emotion has seemed entirely fake.