Have a look here at the cover discovered by Abed Najjar, sent from Victor Hugo in the Channel Islands to his publishers in Brussels. There are three PL77 on the cover and it has been the subject of some dispute as to whether it is genuine or not. I think you'd have to be pretty stubborn to deny it is genuine. http://victorhugocover.com/
Not necessarily. The article in The London Philatelist is worth studying. It is is nowhere nearly as frivolous as this website tries to portray. Some of the contentions in this website are suspicious just because they use such overheated rhetoric.