Everyone is born muslim. Your parents just change you into whatever religion you are. Then you get older and decide for yourself what religion you want to or not to follow. But in the beginning you are Muslim.
Capital D from All Natural is a muslim. Napeoleon from 2pacs crew is a Muslim and said 2pac took his shahadah a few days before he died. So only Allah knows who is muslim and who is not.
Also, about the Malcolm X thing, he left NOI because he found the true teachings of Islam and found the truth the real Islam, that he felt comfortable with.