Yes.
There will be a load of patches it needs tot ake you from DVD Relase TBC (2.0.1?) to the latest (3.1.2) patch.
Even though it's just TBC, it needs to know how things around it will work, including all the armor, models etc that you will see wandering around in certain zones.
If you go to the wowwiki patch mirror site, I seem to recall being able to DL a "update rollup" patch that will be alot faster than using the dumb ass blizard downloader.