Well, Diogenes includes it in Epicurus's list of works. I realize that's not definitive, but KD holds together much better than Vatican Sayings which is definitely a compilation. Could a scribal error have mixed up some sections of KD? Definitely! Does KD have it's overall organization in a work by Epicurus? That's my position. And Epicurus didn't have to call it KD though I don't see why he couldn't. But I'd want to check references to such a work in Seneca, Cicero, and Philodemus et al. before staking a flag too deep:
Such, then, in number and character are the writings of Epicurus, the best of which are the following :
Of Nature, thirty-seven books.
Of Atoms and Void.
Of Love.
Epitome of Objections to the Physicists.
Against the Megarians.
Problems.
Sovran Maxims. Κύριαι δόξαι
Of Choice and Avoidance.
Of the End.
Of the Standard, a work entitled Canon.
Chaeredemus.
Of the Gods.
Of Piety.
[28] Hegesianax.
Of Human Life, four books.
Of Just Dealing.
Neocles : dedicated to Themista.
Symposium.
Eurylochus : dedicated to Metrodorus.
Of Vision.
Of the Angle in the Atom.
Of Touch.
Of Fate.
Theories of the Feelings--against Timocrates.
Discovery of the Future.
Introduction to Philosophy.
Of Images.
Of Presentation.
Aristobulus.
Of Music.
Of Justice and the other Virtues.
Of Benefits and Gratitude.
Polymedes.
Timocrates, three books.
Metrodorus, five books.
Antidorus, two books.
Theories about Diseases (and Death)--to Mithras.41
Callistolas.
Of Kingship.
Anaximenes.
Correspondence.
Edit: Oh, his Wikipedia article lists the work as Fundamental Propositions. I like that!