One of Nick Mordin's books mentions this, and they are all well worth a read. If memory serves light horses, for example, tended to prefer to be drawn outside and run in the clear. Of course they aren't all alike, but watching races closely can give some clues.
That said, I think there is real value in knowing the post position tendencies for each track, surface, and distance combination. You just have to know how to measure it.
