Acura stereo code...plz help

i bought a civic recently which had an acura head unit in it. i disconnected the batt. to the car while working on it one day and i noticed that i didnt have the code to the stereo. i was wondering if anyone could help me. thank you for your time. i have the serial and ref number as well. people say i can go to the dealer but since its from another car i dont know if theyll give me the code to the stereo. so if anyone can help thanks.