Concert pitch means that the instruments aren't
transposed. POA is a transposed score, like virtually all of Williams' orchestrators' manuscripts. So the horns would indeed be a fifth lower, the trumpets a major second lower, etc. With handwritten full scores for films, it's generally safe to assume that they're transposed, not in concert pitch, unless they actually say "concert score" at the top, as is sometimes the case with JNH scores, for instance. However
, Williams sketches are always in concert pitch, and they don't say so.
Basically, when in doubt, pull out a cue that you've got the recording for, listen to it, and then play the part of a transposing instrument on piano. If the pitch matches, you're looking at a concert score - if you're off by a fifth or a whole step or whatever, then you're looking at a transposed score.