The absence of evidence is not proof. Here’s one small example:
Matthew Roper in a FairMormon Blog on June 17, 2013, writes about a criticism repeated many times over the years about the mention of steel in the Book of Mormon. In 1884, one critic wrote, “Laban’s sword was steel, when it is a notorious fact that the Israelites knew nothing of steel for hundreds of years afterwards. Who but as ignorant a person as Rigdon would have perpetuated all these blunders.”8 More recently, Thomas O’Dea in 1957 stated, “Every commentator on the Book of Mormon has pointed out the many cultural and historical anachronisms, such as the steel sword of Laban in 600 B.C.” [9]
We had no answer to these critics at the time, but as often happens in these matters, new discoveries in later years shed new light. Roper reports, “It is increasingly apparent that the practice of hardening iron through deliberate carburization, quenching and tempering was well known to the ancient world from which Nephi came. ‘It seems evident,’ notes one recent authority, ‘that by the beginning of the tenth century B.C. blacksmiths were intentionally steeling iron.’” [10] In 1987, the Ensign reported that archeologists had unearthed a long steel sword near Jericho dating back to the late seventh century B.C., probably to the reign of King Josiah who died shortly before Lehi began to prophesy. [11] This sword is now on display at Jerusalem’s Israel Museum. The museum’s explanatory sign reads in part, “The sword is made of iron hardened into steel, attesting to substantial metallurgical know-how.” [12]
—Elder D. Todd Christofferson, "The Prophet Joseph Smith", Brigham Young University-Idaho Devotional, September 24, 2013.