Nope. The DOI says what it says. The teacher is teaching history. It would also not be a violation to discuss what is known about the religious beliefs of the writers of the DOI, and how it may have influenced what they wrote.
Now, if the teacher teaches whether or not those religious beliefs are right or wrong, then that would (IMNSHO) be a violation. Leading the students in any kind of religious exercise, or supervising the class while a student did so, would also be a violation.
The Pledge of Allegiance says what it says and whats more the SCOTUS has ruled that nobody can be forced to say it. Therefore, those that do say it do so voluntarily and those that wish to omit the words "under God" may do that as well. I don't have a problem with that, why do you have a problem with those of us who prefer to say it?