Wirelessly posted (BlackBerry8800/4.2.1 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/100)
Yep. Once someone puts a sim card in even if they don't do anything but turn it on. The carrier will know.
Since u already reported it stolen, I'm pretty sure it has restriction on you're sim card/acct at a minimum.
If the device is turned on with your sim they will know. And if it was a criminal investigation they could actually triangular its approximate location.
But they won't do that in this case.