Yes, that's where you need to make the changes.
lb_xxx changes the data in iTunes, db_xxx changes the data in iBooks.
And you don't need to run from source, you can just add your modified driver.py file to your installed calibre:
Code:
c:\Program Files\Calibre2\Lib\site-packages\calibre\devices\apple\
The driver has been stable for several months.
G