Werthead
Explorer
They're the same place. I think they misspoke and meant west, although Western Oerik is so massive that it's almost an equal distance (and probably faster sailing east, depending on the trade winds).So 2002 Chainmail for the western continent and Black Moon Chronicles for the eastern. That's really interesting!
Now, if only the latter had a gaming-focused write-up.
As with any discussion of Oerth geography, Anna B. Meyer's website should be your first stop. Her research and analysis of the geography has been outstanding for some decades, and apparently WotC consulted her site in the preparation of the maps in the new DMG. DH Boggs also has some nice maps where he tries to reintegrate the Blackmoor setting (Dave Arneson's home setting) into Greyhawk, using both the original Darlene and Anna's newer maps.
Although the shape/outline of the landmasses beyond Oerth are canon (they're fully codified in the 3E 2001 Living Greyhawk Gazetteer, the last major Greyhawk sourcebook published to date), they're too well-established now, the lands/empires in those landmasses are probably still not canon. The rebooted Chainmail spluttered briefly and died, and the French TTRPG I don't think had official permission from WotC to make those lands part of Oerth, so it's just assumed/implied they are but certainly nothing they did has any bearing on WotC. I also don't think WotC are going to be too fussed about contradicting 30-year-old Dragon Magazine articles.
It's also clear that WotC have an aversion to planetary-scale maps/campaign settings. They've ignored all the lands beyond Faerûn in Forgotten Realms since the last Al-Qadim material was published in 1994 and I don't think Taladas or Adlatum are even mentioned in the new Dragonlance stuff. If they do expand on more Greyhawk adventures in 5.5E, I'll be surprised if they venture outside the Flanaess.