This chapter also looks at the Gog Magog conflict. Here, specifically, whether this is the same war as Ezekiel 38 or not, the falling of the troops here is explicitly on the mountains of Israel. God is said to send fire upon Magog and those who inhabit the coast lands. The nations, seemingly all, then know that the Lord is the only.
The specifics of this chapter make it clear that this has not been fulfilled. Equating this with the Gog and Magog of Revelation 20:7-10, v9 says there is at least seven years between this event and the second coming, but, as that final day and hour are unknown to all but the Father, the actual time between this invasion and the final end are completely unknown.
In this day, God will set his glory among the nations (v21), which will result in judgment. Israel will know God from then on. God hid His face from them because of their sins, but He is promised to restore His kindness to them, and to save them as a people, according to the rest of this chapter.
This is the “all Israel shall be saved” of Romans 11.
So long as one takes vv28-29 as talking about the same event, with no clauses for gaps between them, this must be seen as yet future. God did regather the peoples in times past, after the Babylonian invasion, but it was never accompanied by the outpouring of His Spirit upon the nations, as per the question in Acts 1:6. The apostles of the Lamb received the Kingdom, in the company of the 120, but the nation as a whole did not.
But, God has promised that He will, in the context of this Gog Magog conflict, no longer hide His face from Israel, but He will pour out His Spirit as they turn to Jesus Christ for salvation. Not just a company, but upon the house of Israel.