[ Ref. https://youtu.be/9B8GppgvWzk
 ]

Keith, Greetings from The Bronx! Good news: in answer to your
question in 211101 MMD, the name of the unknown music box tune
is "La Petite Valse". Here is a MIDI file link of said tune;
please enjoy!

https://www.mmdigest.com/Attachments/21/11/03/mime.211103_200329_fredsorchestrion@aol.com.PETITVAL.MID 

Dale F. Rowe
Bronx, New York
fredsorchestrion@aol.com.geentroep [delete ".geentroep" to reply]

 [ "La petite valse" or "The Petite Waltz" was composed by Belgian
 [ pianist and dance orchestra conductor Joe Heyne (1904-1978).
 [ The first recording of the song was released in 1948; visit
 [ https://www.youtube.com/watch?v=7P6f9qndMwQ
 -- Robbie