4WD Pirate with Encoders?

Hello,

I just purchased the DFRobot Pirate - 4WD Arudino Robot Mobile Platform but to my mistake, I realized I needed to add two encoders to the front two wheels. If I purchase the gravity: TT Motor Encoders Kit, can I simple just use those and add them to my existing platform? I'm afraid they won't fit into the body of my existing Platform. Any help would be appreciated, thank you.