I've got an iPhone 3GS that someone gave because it won't turn on. She said it was a 16gb. The back of the phone isn't labeled. Someone else told me that meant it was an 8gb. I searched the Internet and couldn't find anything. Is there any way I tell what GB this is. Model # is 579c-a1303a. From what I've read this just means its a 3GS. Thanks