Bought the game the first day and got a promo cd.
Sounds like the 3rd track is played by a string quartet, (2 violins, bass, cello), accordion (of course) and piano, even though the artists are called the "Layton Grand Caravan Orchestra".
It's the same music as heard in the LTT trailer.
I like the music series a lot, more than the game itself.
First Game was pretty good but tough.
The official osts come out next month or so.