Compare these two quotes from the January 1, 2007 Watchtower page 30 and 31:
"The First Resurrection"--Now Under Way! (page 30, para 18)
18) God's Word does not disclose a precise date for the first resurrection, but it does reveal that it occurs over a period of time, during Christ's presence. The first to be resurrected are anointed Christians who died before Christ's presence began. As Christ's presence progresses, anointed Christians who faithfully finish their earthly course are changed "in the twinkling of an eye" into powerful spirit creatures. (1 Corinthians 15:52) Will all the anointed receive their heavenly reward before the war of Armageddon? We do not know. We do know, however, that in God's due time, all the 144,000 will be found standing on the heavenly Mount Zion.
Questions From Readers: What is the sealing referred to at Revelation 7:3? (page 31)
When will the remnant of anointed Christians who have initially been sealed receive their final sealing? Any still alive on earth will be sealed "in their foreheads" before the outbreak of the great tribulation. When the four winds of tribulation are unleashed, all of spiritual Israel will have been sealed in finality, even though a few will still be alive in the flesh and must yet finish their earthly course.