It would likely have been easy for Joseph Smith to mistakenly describe armor in the Book of Mormon the way he might have seen in the Bible.
William J. Hamblin explains:
warfare in the Book of Mormon consistently sounds like that in Mesoamerica before the European conquerors arrived. It differs from the ancient Near East in those features where Mesoamerican warfare differs from the ancient Near East. Coats of mail, helmets, battle chariots, cavalry, and siege engines—elements prominent in Bible lands—are all absent from both the Book of Mormon and Mesoamerica. If Joseph Smith were copying from information in books available to him, like the Bible, Josephus’s histories, or books about the Romans, that described ancient wars, he would have included those features. Instead, the Book of Mormon leaves out those features of armament frequently mentioned in biblical and classical sources but absent from ancient Mesoamerica– William J. Hamblin, “Warfare in the Book of Mormon,” in Rediscovering the Book of Mormon, edited by John L. Sorenson and Melvin J. Thorne (Salt Lake City, Utah: Deseret Book Co.; Provo, Utah: Foundation for Ancient Research and Mormon Studies, 1991), Chapter 22.
How would Joseph Smith manage to avoid such an easy error?