Yes that's the one. Here's a link that will show a drawing. The end plug is designed to fit in the notch at the end of the handlebar so the grip clamp has surface contact on the entire circumference.
http://bontrager.com/technology/info...ndlebar_system
If anyone is considering this bike, or any other Trek model with this bar system, and want's to be able to ride any distances (and who wouldn't) I would ask your LBS to change it out so you can add bar ends.
If anyone who works for Trek is reading this: you blew it.