Although it had been commanded that this part of the record of Ether should not be written before Christ’s appearance in Bountiful, that had happened, and therefore Moroni could receive the commandment to write them.
The next statement appears to refer to a future event, but it is related in past tense. Moroni says that he was commanded to write, and he did. He was also commanded to seal up “the interpretation thereof” and to include the interpreters so that they could be made known. This conforms with the command to Ether to write, but that his writing would be sealed up (Ether 3:27). However, in that verse, the sealing appears to be related to the vision of the future.
A possible reading is that there were two parts of Ether’s story that were sealed. The first was his experience with the premortal Jehovah. The second was the revelation of the future. Perhaps Moroni was permitted to only write the first part. The second part remained sealed, and has yet been allowed to come forth.
The part that Moroni included was to come forth to the Gentiles at a future date, and if those Gentiles were faithful to God’s commandments, then they could have the same blessings as the brother of Jared.