SnapLock is a persistent property of both the SnapLock volumes and the files on SnapLock volumes. It is strictly enforced regardless of the state of the licensing. SnapLock requires a separate license. You need a license only for the creation of new SnapLock volumes and for the committing of files to the WORM state on SnapLock volumes.
However, even if a license is uninstalled, the existing SnapLock volumes are accessible for general reading and writing.
You can unlicense SnapLock, but files that are already in SnapLock state retain their immutable WORM protection. The only disadvantage of removing the SnapLock license is that you can no longer put new files into the WORM state or create new SnapLock volumes.