While they are technically published while 3e was the actively supported rule system, neither of those books has hardly any rule content in them. No feats, no prestige classes, no alternate skill uses, no spells, no equipment. Nation entries are listed in proper format. Deities do list their domains and favored weapons though.
I'd recommend looking for the Dragon magazine issues with the regional Greyhawk feats (I forget the issue numbers. #315 amd #319.
Also, find the old Living Greyhawk Journal articles in Polyhedron/Dungeon.