I have just bring my new i4 home, and right after I opened the box I noticed a uneven spot in the metal band, left side approx 1 cm above antenna and 0.5 cm long. Its really visible on the certain angel turned into reflection with light. It looks like different alu on that part, whitish blotch. Is that normal? Some kind of coating that apple put on? Eligible for exchange? I have tried wiping with microfiber cloth w/ water but it wont go away.