Yes, that is also my understanding of how things work.
https://support.plex.tv/hc/en-us/articles/200878643-Sign-in-to-Your-Plex-Account
Some Plex apps—usually those designed for use on your television—will let you link the app with your Plex account using a one-time code. You’ll see a 4-character alphanumeric code in the app.
