Do Apple stores keep different configurations of MacBook Air's?

I am looking to purchase a new MacBook air in the coming week and would prefer to go and pick it up from an Apple store as opposed to getting it delivered (put it down to impatience 🙂). The Air that I want is the 13" base with the ram increased to 8 gig, will the apple stores hold stock of different configurations of macbook air's or would they only keep the standard models in stock?

Also while I'm posting, what identification would I need to bring with me to show that I am ellegable for the higher education discount? 🙂

Thanks for any help!