On Larrivee's website under FAQ's Jean Larrivee says that although light strings are recommended-there's no harm in using medium gauge strings. I still agree with the posters above that you may want to make sure there's no problems that could arise from higher tension. I usually take my new (and used) guitars to a good luthier I trust to do a set-up.
By the way- I purchased a Larrivee 0M-03 in January and still have a crush on her everytime I open the case. Hope you like it!
Mike