Do you have to know you are one to be one? The 12 were sent out-Acts10. Paul and Barnabas wre sent out- Acts 13.
Paul and his coworkers church planting was evangelism among the unreached. They had a measure of rule where they had introduced the gospel (I Cor. 10). Corinth was one such cgurch and it wa the seal of Paul’s apostleship in the Lord.. (I Cor. 9). But apparently the itinerant preacher Apolls was an appstle (I Cor. 4.)