Do you mean a blanking centre cap for the wheel itself? In which case looking at the wheels this will not be possible because the drive flange sits proud of the wheel.
If you mean the drive flange (the star shaped piece) that is likely to be part number RUC105200 for your vehicle but you would need to check against your vin number as I believe 2006 was the change over year.
If you mean the black rubber cap on the drive flange that is part number FTC5414