No, parole does not effect free speech. However, again put two and two together:
If anyone in this thread has researched his situation properly you would know he needs to be on very good behaviour.
Vikernes' verdict and sentence was ultimately determined by media, not by law. Despite him being a murder, his sentence was extremely severe by Norwegian justice system standards, everyone knows this.
Strong far-right political association (well, at least publicly) from him will only land him back in jail again. He needs to be very careful in how he handles his public dealings and any political statements he makes need to be somewhat conservative in strength.
Even his relationship with Cymophane Productions needs to be cut off, if it hasn't already (seems to be, given they're not releasing the new record).
Everyone expects comments of extremism from him, but rest assured he is being closely monitored by the Norwegian justice system. They will not be lenient with him by their standards.