Now now...no need for sarcasm.
Nobody said they "know" the one pictured is perhaps fake, it was simply offered that in ones opinion, it is not "authentic". I have my doubts of it being real because there have been a lot of reproductions coming out of Argentina in recent times that have been made to look aged, and that particular sign is listed on eBay as a sign from Argentina, but being sold and advertised in the US with shipping from abroad. Suspect? Yes! Positive? No!
I myself wouldn't buy a porcelain sign from Argentina even if I thought it was real, but that's simply me. And again...just an opinion.