It really is up to you... on public domain works you
ARE the publisher of this version. It's usually not possible to ask the author what they want at this point
so do what you think best.
Are you trying to faithfully reproduce the p-book in an electronic format? (*shudder* not practical) or are you creating a new version (with a new cover, etc)??
Personally, I get rid of them. I almost always have some kind of backmatter (about the author, also-by, copyright, etc) that shows the story is ended...I have no need of "The End".
~The End~