Skeptics.SE regularly receives on-topic questions of the form "Did Person X say Quote Y?"
The answers fall into a few categories:
- Yes, they said it at Event Z.
- No, Person A said it, at Event Z.
- There's no evidence Person X said it.
That last one has an obvious follow-up question: "Who said Quote Y?" or more precisely "Has anyone of note ever asserted Quote Y?" (as opposed to using it as a joke or aspersion).
Is this question on-topic here?