No manufacture should have a prototype ready to go right now, so I call bs on the rumors.
They have several months before they need to have a 2020 engine ready, so any manufacture worth their salt would be focusing on squeezing every ounce of performance out of their concept. Producing a race ready prototype now, is just a waste of time and money, because it will most likely be outdated by the time the actual 2020 season roles around.