Here scribe 2 of 𝓟 initially wrote “with their own hand for their support”; then almost immediately he corrected the singular hand by inserting inline a plural s at the end of the original hand. There are many instances in the manuscripts of the singular hand and the plural hands being mixed up; see the list under Mosiah 16:1.
Elsewhere in the text there are nine more instances of the phrase “to labor with one’s (own) hands”; all of these take the plural hands, including a nearby example in Mosiah 27:5, the next verse: “yea and all their priests and teachers should labor with their own hands for their support”. None of the nine other examples show any variation in number for hands.
Summary: Accept scribe 2’s virtually immediate correction in 𝓟 of hand to hands; the text is consistent in that only the plural hands is found for the verb phrase “to labor with one’s (own) hand(s)”.