If you go to Settings> Home > menu after updating the Search app, you should find the new name of the launcher staring you in the face. And those of you who sideloaded the Nexus 5 launcher on their handset should see a splash screen (image below) after the update.
Does this all mean that the heralded Nexus 5 Google Now launcher will soon be made available to other Android users via the Google Play Store? Stay tuned.
Splash screen for the newly named Google Now Launcher