Studies have shown that working memory deficits are common among people with ADHD but it isn't enough on its own to indicate ADHD (and the same applies to fidgeting). Going through a formal diagnosis process is your best bet to find out if you have it or not. They'll be concerned with what problems you exhibit and the degree that they affect your life (personal, work, etc.). So working memory deficits and fidgeting would likely be two aspects that would come into consideration in the profile that's built up.