I think it's great that the school initiated the Math Subject Acceleration, which should be a good way to test the waters.
I think that it's reasonable to ask the school to do an IQ test, afterall, I'm guessing that they don't have 'handfuls' of kids in the third grade who have scores just like him. If the school doesn't want to, you can certianly get one privately to help with these kinds of questions.
It sounds like your son is happy at school, and eager to learn. If he isn't behaving in 'perfectionistic' ways or avoiding taking intellectual risks, then it seems like he is on a good path. You can always institute 30 minutes of 'Afterschooling' 5 days a week where you assist him to find material that actually is somewhat challenging, and then allow him to demonstrate what he's learned. When you see how he handles stuff that is closer to what he is truely 'ready to learn' you will have a better idea if he has been damaged by his school situation.
By having a family tradition of afterschooling, you can be sure that he will have chances to learn the character trait of perseverance, as the years go by.
Welcome Shannon!
Grinity
