Yes, these plates of brass contain the law. However, the true desire of God is to seek a covenant relationship - with you.
"The reason Nephi hesitated when commanded to kill Laban (1 Ne. 4:10–18) was because of the prohibition of the Law—“Thou shalt not kill” (Ex. 20:13). Although Nephi had learned to be governed by revelation, the strictures of the written Law were clear and undoubtedly caused him to pause while he worked out the priorities in his mind. After all, if he killed Laban wrongly, according to the Law it would cost him his salvation. Eventually Nephi learned from these kinds of experiences that the written Law and God’s will were not always identical, and that the will of God expressed in revelation always had precedence over the written Law" (LDS.org).
Covenant-making and covenant people have been in the Lord’s plan since the very beginning, even before the world was formed.
The Law after christ, lds.org
What are these plates?
These plates of brass contain the "contain the five books of Moses, which gave an account of the creation of the world, and also of Adam and Eve, who were our first parents" (1 Ne. 5:11). It also contains "a record of the Jews from the beginning, even down to the commencement of the reign of Zedekiah, king of Judah" (1 Ne. 5:12) and "prophecies of the holy prophets, from the beginning, even down to the commencement of the reign of Zedekiah; and also many prophecies which have been spoken by the mouth of Jeremiah" (1 Ne. 5:13).
"We had obtained the records which the Lord had commanded us, and searched them and found that they were desirable; yea, even of great worth unto us, insomuch that we could preserve the commandments of the Lord unto our children."
1 Nephi 5:21
These commandments are the same commandments that lead Lehi and his family out of Jerusalem and from being destroyed. They are the reason we are here on this land now. We testify that the Redeemer, the author of the Law should come to save the Earth:
“Behold the days come, saith the Lord, that I will raise unto David a righteous Branch, and a King shall reign and prosper, and shall execute judgment and justice in the earth. In his days Judah shall be saved, and Israel shall dwell safely: and this is his name whereby he shall be called, THE LORD OUR RIGHTEOUSNESS.”
Jeremiah 23:5-6
Prophecies from Zenos, Zenock, Neum, and Ezias are contained in the records.
And I did read many things unto them which were written in the books of Moses; but that I might more fully persuade them to believe in the Lord their Redeemer I did read unto them that which was written by the prophet Isaiah; for I did liken all scriptures unto us, that it might be for our profit and learning.
1 Nephi 19:23
These plates can be of great worth to you as well. Come and be one with the redeemer and the God of Israel. Be part of his covenant people.
But because the Lord loved you, and because he would keep the oath which he had sworn unto your fathers, hath the Lord brought you out with a mighty hand, and redeemed you out of the house of bondmen, from the hand of Pharaoh king of Egypt. Know therefore that the Lord thy God, he is God, the faithful God, which keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations;
Deuteronomy 7:8-9
