I must be misremembering then. The last time I used the station was July '00 and I could have sworn it was "Millennium" to go along with the Millennium Wheel, Millennium Bridge, and Millennium Dome. I'd also thought there was some initial discussion about the "North Greenwich" name, as there another nearby station that had used the name previously.No ... it was called North Greenwich from day 1. I seem to recall that instead of saying "for O2" on the maps it said "for the Dome".
I concur about it being "North Greenwich for The Dome" from 2001-2005 for sure, then them using a little sticker over it for The O2.