NEED help very old camera in side lock box

ok it a camera lock box that has to have a three number code (the box was probly made around the 1940'S) AND I CANT DAMAGE THE CASE ITS PART OF THE VALUE OF TH OLD CAMARA THE OUT SIDE IS LEATHER

MY mom is piss at me for closing it and not knowing the code HELP ME FIGURE IT OUT. i am a 13 year old needing help