I’ve been dimly aware that there were two printings of the World of Greyhawk box set, mostly because of the maps, which are essentially identical. But they’re folded differently, with one set folded into smaller squares.
I like ’em: The “square maps” have a pebbly texture to them. Very tactile. I’d always assumed square-maps was the later printing, since the box set’s predecessor, the original WoG folio, has the maps folded into a large format.
The Acaeum page for the World of Greyhawk goes into the differences to what they term the 7th & 8th printings. The variations are trivial, the most noticeable being the maps (the 7th has the small square maps), and Gary Gygax being credited on the box cover of the 8th printing (under “FANTASY GAME SETTING”)… There you go, squint… you see it now…
Anyhow, now I know why I see different maps in these sets.