Copyright clearance letter
Depends. If the letter is meant to be an example reproduction of what was used during the English 1010 course development, then it should stay. If the intention is to present a generic letter, then it should go.
In other words, it's more than just changing a sentence, the entire letter would have to be changed. Which could be done. In my mind, it's a matter of authenticity versus applicability.
You are right, it would require the whole letter to change. I can imagine people copying/pasting and adapting it, in which case, I would prefer a generic letter that is not biased towards the NC restriction. If you have time, and if agreeable, please adapt Draft Copyright Clearance Letter