In dialects of English, we often find the simple past-tense form used in place of the standard past-participial form. In this instance, the original text has “had smote” rather than the standard “had smitten”. Elsewhere, the original text usually has the standard smitten (42 times), but in four cases smote is found. These dialectal examples have all been edited out. For a complete discussion of this usage, see under past participle in volume 3.
Summary: Whenever supported by the earliest textual sources, the simple past-tense verb form should be restored in place of the standard past participle (thus “I had smote off his head” in 1 Nephi 4:19).