After a little googlizing, it appears that some believe Elie Weisel stole the book Night from another victim named Lazar Weisel whose tattoo was A-7713. Also something about mixing in Christian theology into the book to save Jewish souls. Oh and Elie Weisel's not his real name.
Even if all that was true, guess what? That means the book Night is still basically true! If the Nolocausters want to go this route to discredit Weisel, they are confirming the Holocaust in the process.