Oh, Frank, Have I got a deal for you.

My friend Dave Young wrote a little book several years ago entitled
"How Old Is My Music Box?"  Somehow I suspect that you can find your
answer right there.  It lists music box features and the dates that
they started to appear.  You can seldom be exact, but by checking
several characteristics you can usually get pretty close.   I called
him just now and he has a few copies left (it's out of print) and would
be glad to sell you one.  (Dave is a technical writer and his business
includes selling several dozen short books he has written on improving
business processes.)  The book also has a very nice little chart at the
end that lists the first US patent number issued each year for the
first 4 or 5 million patents.  This is very handy for dating almost
anything that has a patent number on it.

Since he doesn't have an E-mail address yet, I offered to act as
intermediary if you (OR ANYONE ELSE ON THE MMD) would like one.  Just
E-mail me directly and I'll send you the details (address and $ which
is post paid).

Regards,
Craig