Canadian Politics Today

The Liberal Party was the right-wing federalist party in Quebec in opposition to the left-wing PQ. He didn't change parties from Conservative to Liberal; he remained in the federalist fold to go fight for Canadian unity...and succeeded.

First of all, it is true that the Liberal party in Quebec is further to the right than the PQ. But that doesn't necessarily mean it would be considered "right wing" or "conservative" when compared to the federal conservatives or conservatives in other provinces.

From: https://en.wikipedia.org/wiki/Quebec_Liberal_Party
In the context of federal Canadian politics, it is a more centrist party when compared to Conservative and Liberal parties in other provinces, such as the British Columbia Liberal Party. It believes in a strong role for government in the economy and supports social-liberal policies

Secondly, even if the Quebec Liberal Party is "right wing", do you really think most voters in other provinces are going to understand the difference? Most people aren't that familiar with the political landscape of other provinces... they will just here "Charest was a Quebec Liberal" and base their opinions on him based on that.