lsb-release -a will not say if Beta or not. Nor will
neofetch if you have Neofetch installed.
I think we currently only know the difference because Zorin 16 Final Release has not happened yet and when it does... Most people will know that they installed the Beta Version before hand.
This may have happened if a brief net drop caused the updater to not complete.
In terminal you may try running:
sudo dpkg --configure -a
sudo apt dist-upgrade