The official website is plexcoin.tech and they have an elaborate white paper available. However, their white paper links to the same links that you cite, and it is also ambiguous in the sense that it does not list the team of Plexcoin or Plexcorp. Their Facebook page is https://www.facebook.com/plexcoin/ and is quite active with news and updates.
I'm going to say there is a 50/50 chance. Everyone should research, and as with anything, go with your gut instinct.