According to Donl Peterson, the Nephite Twelve "disciples" are never referred to as Apostles in the text of the Book of Mormon, with the possible exception of a passage in the book of Moroni. Here Moroni records the words of Christ to them concerning the bestowal of the Holy Ghost: "ye shall give the Holy Ghost; and in my name shall ye give it, for thus do mine apostles." (Moroni 2:2).
Peterson surmises that there is wisdom in not referring to them as Apostles in the Book of Mormon, a book used so extensively in proselyting, since it would tend to confuse those who might assume we were minimizing the status of, or even replacing, the Jewish Twelve in our theology. The Prophet Joseph Smith referred to the Nephite twelve as Apostles when he penned a letter to a non-member newspaper editor in Chicago:
This book [the Book of Mormon] also tells us that our Savior made His appearance upon this continent after His resurrection; that He planted the gospel here in all its fulness, and richness, and power, and blessing; that they had Apostles, Prophets, Pastors, Teachers, and Evangelists; the same order, the same priesthood, the same ordinances, gifts, powers, and blessings, as were enjoyed on the eastern continent" (History of The Church of Jesus Christ of Latter-day Saints, ed. B. H. Roberts, 7 vols., [Salt Lake City: The Church of Jesus Christ of Latter-day Saints, 1932-51] 4:538).
George Q. Cannon explained that "it was with Peter, who was the senior Apostle there, that the keys rested. He was at the head of that dispensation; therefore, those that received the apostleship on this land were to be judged by the Twelve at Jerusalem" (October 29, 1882, Journal of Discourses 23:360) [H. Donl Peterson, Moroni: Ancient Prophet Modern Messenger, p. 59] [See Mormon 3:18]
A Confirming Covenant Witness
Mormon 8 -- Moroni
[Moroni 3, 4, 5, 6]: (Moroni's Reason for Inclusion of These Chapters)
Jerry Ainsworth notes that before writing his book, he had always wondered why Moroni chose to include chapters three, four, five, and six in his book. Given the historical nature of the accounts of him and his father, and considering the circumstances he faced at the time, these chapters always appeared out of context to him. He writes:
It wasn't until I understood the mission of Moroni during the thirty-five years after Cumorah, that I began to appreciate what he had written and why. The seventh, eighth, and ninth chapters of Moroni make it clear that he, and to some degree his father, ministered to and established the church among people in the north countries. That ministry appears to have focused on the development of new branches of the church, baptizing new members, ordaining priesthood holders, and instituting the sacrament among these new converts. Moroni, having performed these fundamental ordinances of the church across the width of the north countries, would naturally write those ordinances. . . . Moroni would have traveled from village to village teaching the gospel, baptizing converts, ordaining priesthood holders, and conducting sacrament meetings under the direction of the Holy Spirit.
[Jerry L. Ainsworth, The Lives and Travels of Mormon and Moroni, pp. 227-228]
A Confirming Covenant Witness
Mormon 8 -- Moroni