A documentary just aired on History Television in Canada about an hour ago. It will most likely be on again in two hours. I enjoyed it. It went a bit deeper into Ballard's search for the two Nuclear Submarines before finding Titanic.
The interior is definitely real, but I don't believe it's from Olympic. It certainly doesn't appear to be. Come to think of it and far as I know, no footage exists of Olympic's interior, but someone can correct me if I'm wrong.
It's probably from a later ship, but I'm not sure which one.