The door of durin.

[Hot, crispy nice hobbit]

Gandalf could have paraphrased it, using the more common term at the time, Moria instead of Dwarrowdelf.

If Gandalf have could read out the inscription on the door itself, why should he need to paraphrase it? He was detailed enough describe the fine and small inscribtions below the main headings.

Gee, I should suppose it is more of an oversight on Prof T's part. Moria is already a common name even among the dwarves. (The name was first mentioned in the Hobbit, by the way) Besides, the dwarves do not live forever like the elves, so they tend to forget feuds or at least what caused them in the first place.