In 1 Nephi 5, when Nephi and his brothers return to the wilderness, Lehi starts examining the newly obtained brass plates. One observation he makes has been noted
here. Then, in verses 14, 17-19 we read:
And it came to pass that my father, Lehi, also found upon the plates of brass a genealogy of his fathers...And now when my father saw all these things, he was filled with the Spirit, and began to prophesy concerning his seed— That these plates of brass should go forth unto all nations, kindreds, tongues, and people who were of his seed. Wherefore, he said that these plates of brass should never perish; neither should they be dimmed any more by time.
The brass plates were passed from one generation of Nephite record keepers to the next. But the most thorough description of this transmission process is found in Alma 37, when Alma-2 hands the records to his son, Helaman. Note what Alma says about the brass plates in verses 3-5 and how it compares to what Lehi originally said:
And these plates of brass, which contain these engravings, which have the records of the holy scriptures upon them, which have the genealogy of our forefathers, even from the beginning— Behold, it has been prophesied by our fathers, that they should be kept and handed down from one generation to another, and be kept and preserved by the hand of the Lord until they should go forth unto every nation, kindred, tongue, and people, that they shall know of the mysteries contained thereon. And now behold, if they are kept they must retain their brightness; yea, and they will retain their brightness
It is obvious that Alma-2 had studied the small plates of Nephi. Perhaps this description was on the large plates as well, who knows, but in any case, Alma makes a clear reference to what Lehi said about the plates when he first obtained them. This is another one of those internally consistent references that draw no attention to themselves.