Yes, he was. The ND/SM Observer of 12/7/05 carried an article that you can get through their archives. Fr. McBrien said under his contract he couldn't discuss his role, but he did discuss his appearance on a TV documentary about the book. Evidently the most controversial part of his appearance were his comments about the possibility of Jesus having been married. He had said, it seems, that he was open to discussing it and that "Jesus' divinity would not be compromised if he had, in fact, been married"; but he said in his column that there is no evidence in scripture or tradition that he was.