The June 30 date is not going to change anything with respect to the criminal law and these firearms. Should a firearms business sell some firearms that are currently prohibited, then they would be in violation of the law. Should a firearms business sell firearms that are currently non-restricted or restricted, they would still be in compliance with the law and therefore not subject to criminal liability simply for transferring or selling the CZ and the Four Seasons firearms.
The June 30 date has nothing to do with the legal classification of the firearms so it has no impact on criminal liability. It's simply a date that would allow a person to be eligible for grandfathering.