My experience has been that GT kids with AS often manage to compensate when they're young, because the requirements of the environment aren't that tough. It can be really tough to tell one way or the other at this age -- sometimes it's obvious, but if it's not obvious, then best to watchful-wait. I know quite a number of kids whose parents were told by an evaluator, "Couldn't possibly be AS" when they were 6, but by age 10-12, the AS was much clearer. (I have in all cases refrained from saying, "I told you so." (grin))
However, I've also seen a pattern that is as you say, more the opposite -- an overwhelming empathy and sensitivity (usually both sensory and emotional). Because a lot of the same shutting-down defenses get used against being overwhelmed, kids are often misdiagnosed as having AS.
It's complicated. Agreed that I would trust Ed Amend, Nadia Webb, or Dee Lovecky to do a thoughtful job of analysis.
