Correct. The BES Express can manage a rather large number of Blackberries without additional CALs.
you even dont need BES provisioning on the Handheld, you can go with BIS if it is ok for your to activate a Blackberry using USB.
The limitation of the BESx is a rather small set of Policies compared to the Full BES.
a comparison can be found here: http://us.blackberry.com/apps-softwa..._021610_v3.pdf