You have probably found the answer to your question by now but, if not, and for others:
Yes there is a model that works at least for rviz (I haven't checked with gazebo).
You can find it in the slamdunk source: slamdunk_ros/slamdunk_visualization/urdf.
For me it worked by entering the command provided by the howto file in this folder then launching rviz with the slamdunk plugin
rviz -d $(rospack find slamdunk_visualization)/rviz/slamdunk.rviz then adding a robotModel en rviz.
I had previously built the slamdunk package on my laptop.
There are probably other ways to do it and you might be able to use the models in the models folder (in slamdunk_visualization again) but this worked for me.