Censorship Board Sticker != Mark of Authenticity
BUT
Censorship Board Sticker = Mark that it had the proper rating and that its 'safe' for sale and public viewing without elements of extreme deciepting explicit, gore, sexuality, pornographic & other undesirable elements dictated by the censorship board.
I dun wish to go into an argument or off-tangent (like I did with so many other threads here) with regards to the word 'censorship'. But lets try to stick on path this time.
We see bootleg (or 'pirated') anime, dramas for sale here. Most of it I believe, are parallel imports from China or Taiwan from obscure companies that do not have the proper licensing and original mastering from the originating country to have the authorisation for duplication and sale. Instead, these companies make use of copies of the original master or even from the original company's DVD/VCD to 'remaster', digitally remove any traces of the originating company and repackage the drama as 'released by XXX company'.
I'm personally not very sure how legal is this. But from my limited knowledge, licensed companies who are authorised by the film/anime makers to sell their films pay a certain amount back to the film/anime company (kinda like a royalty thing). But bootleg producers get every single cent from ur purchase and none of it goes back to the film/anime company.
Of cos, if u want original stuff, there's a price to be paid. If u guys want to be sure that u're buying the real deal, check out the packaging for obvious defects like typos, erratas, bad logo markings, etc. If u're really damn fussy about it, u can go online to see the the authorised retailers and distributors for the movie/anime. Some movie/anime companies have a long running deal with sales companies and lists them down.
The 'Buyer Beware' thing applies here since the question of pirated movies and parallel imports falls in a grey area.