With the update 4gb patch I really do not Know. I seem to remember with the old patch that it would load with nvse so you could launch with nvse. With the update you are told to launch with Steam. If you launch with Steam there is that console command to check and see if your nvse is loaded. However if you launch with nvse there is no way, as far as I know, to tell if the 4gb has loaded.
But, as the 4gb patch is now integrated into FalloutNV.exe it stands to reason that the patch must be loaded however you launch the game.