Here in the printer’s manuscript, Oliver Cowdery corrected scribe 2’s before to by. This correction seems to have occurred when Oliver proofed 𝓟 against 𝓞. The use of before suggests that the laws were acknowledged by someone else in front of the people, not by the people themselves. Clearly, the people were the ones who acknowledged the laws that Mosiah established, as is stated later on in this chapter:
Note here the specific language referring to the laws established by Mosiah: “they have been acknowledged by this people”. It is theoretically possible that Oliver made the change in verse 1 after copying verse 14, but this seems doubtful since there is no independent evidence of Oliver making conscious emendations based on specific readings that far away. In any event, before seems to be an error. There is one passage that refers to acknowledging something before someone: “acknowledge your unworthiness before God at all times” (Alma 38:14). Ultimately, such a reading seems inappropriate for Alma 1:1, even if Oliver edited verse 1 after reading verse 14.
Summary: Maintain Oliver Cowdery’s corrected preposition in Alma 1:1 (“they were acknowledged by the people”).