S-E's pretty good with the iTunes releases.
They have been, but it's far from a guarantee, Black Mages 3 isn't there. And they can occassionally be outright stupid; it's better to import the FFVII and FFXIII OSTs than to buy them from iTunes, FFVII's especially bad because it's missing ONE random track, which means you have to purchase each track individually for a ridiculous sum, at least XIII has the excuse of removing vocals that might have been a pain to license for the US that weren't in our version anyway.