The testing procedure for adults is pretty standardized. You don't need to bring anything - it's their job to determine whether or not you have AS or something else, so you don't need to come prepared to 'prove' anything. In fact, doing so could conceivably work against you, making them feel that you don't respect their education and experience enough to trust their judgment, which might cause the examiner to have a dismissive attitude. It's mostly the Minnesota Multiphasic Personality Inventory (a long-ass multiple choice test), Rorshach inkblots, colored block puzzles, free association quizzes, and so on...you don't need to bring anything or study beforehand.
OTOH: Personally, I'm a 'carrier' - I always have something with me, whether its a huge shoulder tote full of pencils, pens and sketchpads, or just a small notebook and my iPod and keys - I'm just more comfortable having something physical to hold onto and fiddle with, but that's just me. I don't see how that would be a problem.