The differences in the two texts are insignificant. The message is that Assyria was the Lord’s instrument used to punish the house of Israel. In the Doctrine and Covenants the Lord says, “And in nothing doth man offend God, or against none is his wrath kindled, save those who confess not his hand in all things, and obey not his commandments” (D&C 59:21). Assyria is also an example of this principle revealed to the Prophet Joseph Smith.
Although there is nothing said about Assyria’s being given the opportunity to keep the commandments of God in these verses, when the full history is known it will undoubtedly show that Assyria did have that opportunity. This conclusion is drawn from the allegory of the house of Israel in Jacob 5, which outlined the future of the house of Israel. The wild olive branches are the Gentiles, who are to be grafted into the tree of Israel and given the opportunity to bear fruit. That some did bear fruit from this graft is shown by the Savior’s declaration to his disciples to “look on the fields [of the Samaritans]; for they are white already to harvest” (John 4:31–38). The Samaritans were, in part, a product of the Assyrian conquest, as the Assyrians brought Babylonians and others “and placed them in the cities of Samaria instead of the children of Israel.” They intermarried (were grafted) with the Israelites who were left behind when “Israel [was] carried away out of their own land to Assyria” (2 Kings 17:23–24). “The Jews [had] no dealings with the Samaritans” (John 4:9) because they felt they had polluted their birthright (see John 8:48 and the Bible Dictionary in the LDS Bible).