The fullness of the Gentiles came in in the 1st century AD - Paul's commission was to the Gentiles.
(Acts 20:24 But none of these things move me, neither count I my life dear unto myself, so that I might finish my course with joy, and the ministry, which I have received of the Lord Jesus, to testify the gospel of the grace of God.)
(2 Tim 4:7 I have fought a good fight, I have finished my course, I have kept the faith)
All Israel was saved back in the 1st century - when Paul says "all' Israel he is speaking of the full compliment of the remnant of Israel.
(Rom 9:27 Esaias also crieth concerning Israel, Though the number of the children of Israel be as the sand of the sea, a remnant shall be saved)
Paul is not saying ALL Israel would be saved otherwise he would be contradicting himself in the same letter.