I think the answer to the Mandoline question is deceptively simple:
Tim Kramer's music box is missing its 'zither' attachment.

I have an six-tune box that is a bit smaller than his, inlay on
lid, 77-tooth comb, but with the following on the tune sheet:
"Mandoline Tremolo Zither".  (I don't know why all three -- couldn't
they make up their minds?  Seems quite redundant.)

I _know_ it is not a true Mandoline box; however, one does have the
option of lowering the attachment to mimic a mandolin sound, hence the
title.  The tune arrangements are very complex and florid, which only
makes sense with the zither attachment, else why bother...

The tune sheet on my box also bears the same 5-digit number as the
great wheel of the cylinder.

Claudine Jones
San Francisco