Sharon--
I generally agree with your reading of Twain's persona in "A True Story,"
but as you point out, he's Aunt Rachel refers to him as "Misto C"--the only
instance that I'm aware of in which his Clemens' identity is ever alluded to
in print.
So while he depicts himself as woefully unaware of what it means to be
black, and foolishly assumes that Aunt Rachel is the stereotype of jolly
negro that whites wanted to believe in, her identifying him by his true
initial is a moment when the mask of pseudonymity drops.
Larry Howe