I have found a quote attributed to an author, but I have been unable to locate the source of the quote. Is it on-topic to ask for help identifying the source?
In case it makes a difference, the quote is about an elephant's memory by Herb Caen.
There are several examples of such questions on the main site; e.g. Where did the Robert Frost Quote "If we couldn't laugh, we would all go insane" come from?, Who said "Poetry is the art of giving different names to the same thing"?. We've even got a whole tag for it: quote-identification.
I don't think we have any explicit meta decision about it, but if you suspect that the quote is from a literary work it should be fine here (but of course, there's no way to know if it's from a literary source before finding the source, so that kinda defaults to allowing all quote identifications).
Of course, any clues are helpful - so who it's generally attributed to, where you found the attribution, and where you've looked.