I just bought an iPhone5
To ensure my old iPhon4 was backed up i...
1. Deleted the iPhone4 backup from iTunes prefs(devices)
2. I then sycnched the iPhone4 to get a new backup of the old Phone.
I then installed my new iPhone5 from the fresh backup of the old iPhone4
This way i got my new iPhone5 exactly as my old iPhone4
Screens all looked the same, EVERYTHING the same.
Some minor adjustments were needed afterwards.
Hope this helps.