I am not really familiar with these TimeMachine backups, but I assume that whenever you have a Manifest.plist file (does that file ship with the backup?) and itunes_backup2hashcat.pl extracted some "hashes", that you should be able to crack it.
Therefore: 1. search for the Manifest.plist file, 2. use itunes_backup2hashcat.pl, 3. crack it.
Therefore: 1. search for the Manifest.plist file, 2. use itunes_backup2hashcat.pl, 3. crack it.