There were a lot of reasons for choosing a dit name, and depending on how far back it was added, the dit name may have become the family name. Or the family name may have become the dit name...

You can never have too much confusion

Ordinarily, I wouldn't even mention the subject, but it seems you are really dealing with a dit name, so you should be aware of the possibilitites. Here's a decent article on dit names, and there are others...try googling...
http://www.francogene.com/quebec/ditnames.phpOne thing that may be to your advantage is that Labrie is not a common Quebec name...if you were researching Simard or Charbonneau it would be a different story

So you may have great success...

Cheers,
China