score:3
Does the lack of any indication of a period of entry mean I was authorised for the full 6 months?
Exactly so! If given less, the exit date was written.
I say "was" because Canada doesn't stamp passports anymore.
Upvote:1
Yes that what it means. You can stay in Canada for 6 months. That is based on my personal experience.
You are allowed to enter Canada as a visitor for 6 months. If the officer authorizes a stay of less than six months, they will indicate in your passport the date by which you must leave Canada.
http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=1016&top=16
If you want to stay longer than your authorized stay, you should apply for an extension at least 30 days before the authorized end of your stay.