You say that you were "unaware" of the the state's firearms law, but as old saying, which you've probably heard, goes, "ignorance of the law is no defence": not knowing the law is not a defence to having violated it. It is possible that the prosecutor will elect to voluntarily dismiss the case given the facts; it is also possible that if you go to trial (rather than take a plea deal, if a favorable one is offered) that a judge would choose to dismiss--but they don't have to. You can be held strictly accountable for violating the firearms law.