I did that upgrade today also. It was seemingly the same after the soft reboot. So, I did a hard reset (knowing I would lose everything since the V2 upgrade.. which wasn't much). Turns out, it went back to the white screen.. had to reimport the v2 hack registry again, had to reimport the ie4 reg hack.. did a soft reboot. made the reg mods for the cursor (though I updated the reg in the /ifc dir to reflect that mod).. then ie4 seemed to look a bit different..
Yes, I probably could have just copied the files over to the windows directy also and soft reboot but I've never been one to do things the easy way...
I was not sure how to tell if it was truely ie4 other than looking at the file size in the windows directory. Since the file size is the same as the update, I assume its correct.
It seems to work well regardless.