Question: Will someone with asperger's syndrome come out at tell you the first time that you meet them that they have Asperger's ?

I ask this because I know that there are different severeties and what not but my brother has Asperger's and I know quite a bit about it and this kid doesn't seem like he has Asperger's. He is very flamboyant and always wants to talk and always wants to be around people. He doesn't take social ques well which I know is a symptom but when ever he introduces himself, he always says "Oh, sorry am I being anoying I have aspegers and ADHD so I don't know". It annoys me because if he is lying than I don't know what to do but if he does then I feel really bad for not believing him, but everything I have read says that they are social awkward and they don't socialize well and what know. Thanks for the Help!!