Here Oliver Cowdery corrected word to words by inserting an s; the level of ink flow remains unchanged, so the correction appears to have been nearly immediate. Similar plural usage is found, for instance, in 2 Nephi 9:54: “on the morrow I will declare unto you the remainder of my words”. More generally, the Book of Mormon text usually uses the plural words when referring to the word(s) of a person; for discussion, see under 1 Nephi 16:24. Here in Mosiah 4:4 the virtual immediacy of the correction in 𝓟 suggests that the plural words was the reading of the original manuscript.
Summary: Retain in Mosiah 4:4 the plural words in “the remainder of my words” (the corrected reading in 𝓟).