you can do a name search on the courts website in your state, i believe it was general district court traffic division, and once you do that, it will spit out your case and the disposition status, you could print that.
oftentimes, when I got a call from a customer, I would do a letter for them stating the charge and that the fines/costs are paid and that there are no open dispositions. your court can't do that? (disposition letter)
i'm sure the IO can see in their system if it's all "done" or not... but it's def. good that you included that in your N-400. when did you file your N-400?