That is what 小花生 is worrying about this days.
As I know generally a approval notice for I485 is
This case has been approved. On *****, 2005, an approval notice was mailed. If 14 days have passed and you have not received this notice, you may wish to verify or update your address. To update your address, please call the National Customer Service Center at (800) 375-5283.
Maybe differnet center has different approval notice.
Still wish your case has been approved.