No It is likely that the behind closed doors E3 demo will be shown to the public but nothing is certain.
It is
very likely there will be new footage.
1. This is Bethesda's own convention
2. The game is 3 Months from release
3. The public has already seen half of the E3 demo.
4. The press needs to see something new.
5. Todd's probably tired of presenting the same demo that's been shown since April.