Soooooo.....if I didn't pre-order.....

You'll be fine. I'm walking in for a gift, so I'm not too worried. Most large stores around big cities are going to receive or have stock. I'd just play your cards right, hit the areas that are the least congested if you're really concerned. I honestly don't see either of these launches as big as what people are hoping for. Especially because the accessibility of the online ordering of Target, Walmart, TRU, hhgregg, Costco, Best Buy and Amazon in the year 2013.
 
I stopped by my GS tonight to get my midnight launch group number and was told they had about 50 extra for walk ins. They already had 50 people outside in a separate line so those systems are all spoken for and that line was cut off.