There is always a tendency to describe Book of Mormon ordinances in latter-day terms. At first glance, this passage appears to indicate that Alma is bestowing the gift of the Holy Ghost by the laying on of hands. However, he is "clapping his hands" upon fellow laborers who had been members for some time. Amulek, Zeezrom, and two sons, Shiblon and Corianton were Alma's companions, and it is not likely that they never had the Holy Ghost prior to this occasion. Amulek in particular has already taught great things by the power of the Spirit (see Alma 11). Therefore, Alma must have been setting them apart to perform missionary work among the Zoramites. Hugh Nibley referred to this instance as a setting apart (see Teachings of the Book of Mormon, Lecture 54, p. 435).
"The text of Alma 8:30 indicates that Amulek had previously enjoyed the Holy Ghost. The same gift must also have been enjoyed previously by the others. We should assume, then, that Alma was able to bless his brethren in this particular instance with a special manifestation of God's goodness." (Sidney B. Sperry, Book of Mormon Compendium, chap. 28)