According to the Catholic church, was there a New Testament writer who was not a bishop?

When writing [my answer](https://christianity.stackexchange.com/a/90846/10672) to another question about the teaching authority of the NT writers (as Magisterium), I was wondering whether any author of the 27 books of the New Testament was *not* a bishop? We can exclude the anonymous author of the *Letter to the Hebrews*. We know that Peter John, Paul, James, Mark, and Jude were bishops. **How about St. Matthew and St. Luke; were they bishops as seen by the Catholic church?**