@lolakulu
I did some digging and found this:
Play Install Referrer Library ported to Unity. Contribute to uerceg/play-install-referrer-unity development by creating an account on GitHub.
github.com
^ this one is for Unity, but there are different wrappers/methods with similar names, and IDK if this is the exact one that was used for this game or if there are other libraries that do the same for unity.
Google Play has something called "
Install Referrer API" that lets apps track where the install source is from, so on the apps first launch there may be a flag like getInstallReferrer() or INSTALL_REFERRER that triggers which version of the game the user gets
Perhaps this can help?