Yes, but not without a lot of effort.
MUGSI releases your Undergraduate Personal Timetable, in which you could find your schedule. This year, it happens in August 8 for the Fall/Winter session. It gives you a (usually) completed timetable, and you have If you are satisfied with it or not.
(This part, you could do before the timetable is released, but you may find that you're stuck in certain labs/cores/tutorials, because others are full.)
You could find when cores (C--) (lectures except in Psych 1X03/1XX3), tutorials (T--), and labs (L--) are through this link by entering the course's details:
https://adweb.cis.mcmaster.ca /mtt/
Then you have to plan out your courses by making a mock timetable. Here's a guide for that:
http://www.macinsiders.com/showthread.php/make-mock-timetable-22732.html
After that, you just change the sections on SOLAR. Note: You can't change it before the timetables come out.
tl;dr: Yes, you can plan them. Yes, it helps to have a mock timetable to organize what you want.