I found a lovely simple wooden music box at a second hand shop. Its quite heavy and in good condition. Its by Reuge and plays the song "Edelweiss by Richard Rodgers. I'm not sure what this means: CH 2/50
But that is on the lable on the inside of the box.
It looks on the older side like maybe from the 70's So I'd guess its around 30 to 40 years old but I would like to know for sure. Dose anyone happen to know how I may find this out?

Thank you!