My hunch--and it's no more than that--is that Twain had some hand in that
title. Perhaps it was a joint creation?
Not that this would prove anything, but I was wondering if anyone can recall
Twainian uses of "gilded" or its variants from BEFORE the novel was written?
It's easy to find examples from writings that came after:
The "gilded device of some kind" on the steamboat in the huge second
paragraph of "Old Times..."
Most obviously, the gilded dome of the schoolmaster in Tom Sawyer
The seventh law of good writing in "Fenimore Cooper..." which states that if
someone talks like a "gilt-edged [volume]" at one end of a sentence, he
shouldn't talk like a minstrel at the other.
I'm sure there are other instances. But more important, the underlying
notion of something that is sham-elegant on the outside but not so lovely
within seems to me very near the heart of Twainian satire. For example, The
Innocents Abroad teems with "gilded" visions of Europe, whether or not he
actually uses that word.
I don't believe Clemens had much to learn about gilding from Warner.