As I mentioned in my comment the answer is yes. The whole point of a rules system like Drools is that it allows you to take what is traditionally hard coded branching/conditional logic and capture it externally (not code) so that it can be easily changed on the fly.
With Drools, a very simple approach could be to store the rules files external to your jar/war/ear and put a file watcher in them to reload them if they are updated. This is very basic but would work. For a more advanced approach, I believe Drools supports a versioning and deployment concept (via Guvnor) that allows you to maintain and hot deploy multiple versions of your business rules; sort of the approach I described on steroids.