The anodized portion has been grounded and polished off on the chamfer. If you watch the iPhone 5 official video from Apple from 5:00 - 5:12 time mark, you'll see the anodized frame going thru grinding and polishing for the chamfer. I doubt that they anodized it again but instead just painted it and that is why that chamfer portion is easily susceptible to scuffing.
I have not watched it - however, if that process is what was done we may have something to worry about.