Buffs granting AP, were granting ONLY MAP.
I'd like to clarify that, too. Some buffs were changed over time to cause less headaches to buffing groups. You might wonder why a hunter would be upset at getting a
Blessing of Might, or a
Battle Shout since if you read the tooltip carefully, it only granted melee attack power, and not a flat AP buff. Or why hunters don't get to use
Hunter's Mark in raids with 8 debuff slots, since it only affects ranged attack power. These were a direct affect to AP for either melee or ranged.
You can also get into "passive" AP boosts, that aren't directly saying they give AP to certain classes. Shaman totems come to mind, mainly,
Str totem and
Agi totem. The Agi would generate AP for rogues, catform, and hunters. While as Str would give AP to rogues, hunters, shamans, and warriors, only sham-rogue-war would benefit from the AP since it gives melee AP. Hunters would be left out (unless you want to smack a boss), except for their pets.
It may be silly, but it's one of those things you learn passively as you play.
Edit* Forgot Kitties, since no one brings them to raids. Also left out casters, cause ap for casting is just silly.