Here in the original manuscript, Oliver Cowdery initially wrote “and now the words of Ammon”; later, with somewhat heavier ink flow, he supralinearly inserted these are, giving “and now these are the words of Ammon”. Oliver may have corrected the text here when he read it back to Joseph Smith. There are three other examples where the text uses “and now these are the words” to introduce an immediately following quotation:
Although there are two instances of “and now the words”, neither one introduces an immediately following quotation:
The use of these are in Alma 26:1 is undoubtedly correct.
Summary: Accept in Alma 26:1 the corrected reading in 𝓞, “and now these are the words of Ammon to his brethren”.