Depend on how dedicated you are I guess
TL notes about the old book being covered will make the series even more interesting, but it's not a must since the important point is usually covered in the story anyway. As for the story itself, I don't see many things that absolutely need TL notes, but some TL notes here and there would add even more richness.
Tl;dr, not essential, but it would make it even nicer if it has some.