So I ended up calling amazon since nothing had happened automatically. It was kind of a hassle, but in the end I ended up getting a $1.00 credit to my account.
First, the rep was confused about the preorder price change I was requesting since I had gotten it originally with my gold box($20.99 ->$19.94) and he thought that amazon had automatically adjusted the price. Once I cleared it up that I did not get the price change automatically to $19.99(w/ gold box comes to $18.99), he credited my account the difference for me. However, in the end, I think that the rep was still confused on why I actually called them. I THINK that the rep thought I was calling b/c I just wanted the price changed to $19.99 since thats what it is now. NOT b/c the price had changed to that before it was released, which is part of their preorder price guarantee. So I got the $1 back, just for the wrong reason.