I agree with Jon. To own the other texts is not currently sinful. Even to read them in the interest of finding out about another religions teachings is not sinful.
The scenerio does not let us knos if Joe already owns a Bible.
The Magesterium has a duty to both instruct and to protect the Faith of Catholics. There was a time when few people had the access to information in the manner we do today. Many people believed things just because they were in print. So the Church can restrict reading material if it is determined to be a threat to the Faith or Morals of Catholics. As an example the Church prohibits reading or viewing of pornographic matter. While the DaVinci Code was not officially banned, the Church does warn Catholics that it is a novel, and misrepresents both the Catholic Church, history and Opus Dei.