Not that it's likely to come up at present, but would Matthias be considered a disciple? The disciples themselves gave the qualifications necessary, and found that Matthias fit them. He was also chosen by lot (which in this case indicates God's choice) to take the 12th position. Since there were no further replacements for the original 12 made later, Matthias choice to take the place of the apostate Judas Iscariot indicates the disciples felt they needed a full 12 faithful followers of Jesus as disciples, and Acts states that he was "added to the eleven."
Just waiting for a useful Matthias reprint...