You're right. As far as I can tell, this not her natural hair. I recently saw a biography show about her and they had footage of Oprah anchoring a television show when she was younger. She had type 4 curls in an afro. It looked great. I loved seeing her like that!
During that period, they insisted she relax her hair and they felt her features were too wide apart and asked if she would consider plastic surgery! (Now that's beyond insulting!) I think she went on to AM Chicago, a morning show after that, in which she wore TWA. It was really cute. It seems like she stopped wearing her hair natural when she started the Oprah show.
I respect her hair choices much more now. I think in her industry it's even more unforgiving of natural hair. Even worse than the knuckleheads we put up with in corporate jobs.
I'm glad to see younger anchors and commentators like Amy Holmes are starting to wear their hair natural. That's off topic though, sorry.
I found a video of AM Chicago. Shows Oprah's TWA: