The biology stuff in unit 3 can be found in the pre-2008 unit 4 papers
Only some. pre-2008 study design has a section called 'food chemistry' in unit 4, which looks at carbohydrates. As far as I know, the new study design introduced structures of proteins/DNA.
So really, if you want to practice the the old syllabus stuff, save the printing and sorting and get checkpoints. =]
But really, each year ~10 commercial papers are published for each unit (past VCAA, NEAP, TSFX, LisaChem, CSE/IARTV, STAV, TSSM, Insight, Chemology, Kilbaha), and this is the 4th year, so there are at least 30 papers out there (with 10 to be released) that are for the current study design. Who REALLY needs more than 40 papers per unit?

(Oh, and NEAP smartstudy has 3 papers, A+ exams has 5 or 6, Jacaranda textbook has 1, some tutors publish their own KBT/medtutors maybe? VN might even write our own this year too)