These four verses are Mormon’s comments written about A.D. 385. As suggested above these particular and very large records (v. 13) should fill in many of the geographical, archaeological, and historical questions that have arisen through the years (v. 14). It will also be interesting to read the records kept by the Lamanites as implied by “kept chiefly by the Nephites” (v. 15). Were these Lamanite records also preserved? The converted Lamanites certainly kept records, and it is implied they had been placed with the Nephite records (v. 16). The records kept by unconverted Lamanites may also come forth if and when the Lord wants them restored.
Mormon’s declaration that “they are no more called the Nephites” certainly identifies the time period to which he refers (v. 16), the final destruction of the Nephites occurred about A.D. 385. It also identifies “the end of the book of Nephi” referred to earlier by Mormon (see Helaman 2:14 and comments therein) as the same time period.