Yes, I tested with the 4.0.3 update and it works.
You have to pay attention to the following points:
- The update will not work while the rSAP system files are installed, so uninstall before rebooting. The update checks all system files and will fail if you have modified any file in /system
- You will have to "re-root" your phone after the update.
Be sure to create a backup of your running system before you do anything! I had some problems with different Superuser versions that took me a while to fix...