No - the update was for all iOS device - not just the phone.
Search this site for the many threads that deal with the battery drain issues and see if you can find some help in one of those discussions. I dont know if anyone has come up with anything concrete for this yet.
My suggestion to you would be to restore your device and see if there is any improvement at all. Send feedback to Apple as well if you like.
AFAIK - the update was to fix the battery drain issue in all iOS devices. The actual name of this iOS is iPhone OS 5.0.1 - even on the iPad.
Leave feedback here.
I know that the iPad will sync wirelessly with your PC if you have iTunes open. I had my iTunes set to open automatically, but after my iPad opened my iTunes 3-4 times in an evening, i turned that setting off. So, despite it supposed to be that the iPad would wirelessly sync only if plugged into power, that's not the case. So if you have wireless sync active that could be part of the mystery drain.
If you have iCloud active, it may be doing the same thing. Actively syncing while you think it's just sitting there.
Nothing but pure speculation but there have been some that have said they experience better battery life with iCloud syncing turned off. Could be something you can experiment with.