I don't know if he has it or not and you won't untill you get him tested.
But what ever you do, take him seriously and don't put off what he is telling you.
I know that me being a mother.. none of us want to admit that "OUR child could have anything "WRONG" with him or her.

My mother never knew about ADD or what it could be, other than stubborness or lazyness. The affects were devestating for me.

Let him know that it is important to you to find out what may be the issue and you don't wan't for him to be held back by anything.
If he realy does have ADD then they can find a way to help.
If not, then he will then at least know that his attempts at fooling about were foolish.
But at the very least, don't make him feel dumb for trying to get some understanding on it.
Believe me, that can be VERY frustrating, coming from someone coping with it.
Hope this helps some.
:-))