You think they're stupid enough to blatantly lie outright?
A few factors are at play here.
1) The credibility of Jorge Bocanegra; (Rely On Horror's Castlevania columnist who wrote the article)
Do we take this report at face value? It is the only report of it's kind thus far. No sources named, nothing verifiable. Does he have a history of making things up at all?
2) David Cox, perhaps unintentionally, backs this story up;
He said "I'm not working on the anniversary project". He did NOT say that he doesn't know, no comment, or that it does not exist. Then again, Cox isn't always truthful. Grain of salt here.
3) Konami outright denies to comment on it officially;
If it exists, then this was an unintentional leak of information. This could explain Konami's unwillingness to comment, and why thus far has been silent on announcing it.
4) The credibility of the unnamed source who mentioned it;
It wouldn't be the first time a representative of a game company has lied, or jumped the gun. He is unnamed, and therefor unverifiable. See also point #1.
It really could go either way. It mostly hinges on point #1 to be honest, since Cox is unreliable in all senses.