No, they have not. Panasonic has never said anything like this.But at the same time they have hinted at 3 versions of the GH6. Video, still, and a Jack of all tTades.
This rumour about three GH6 models came from a Spanish (?) site and was all over the place in late 2019 and early 2020 when it was taken for granted that 8k GH6 will be launched at Photokina 2020 (May).
It was quite logical rumour too because that was a carbon copy of panny FF lineup: entry level hybrid, and two very expensive video and stills oriented models.
I'm tempted to believe that when original GH6 development started in 2017 or so, they had plans like this but now we already know that 8k GH6 got cancelled and Panasonic went back to drawing board for more than a year because this new GH6 they officially announced yesterday is something entirely different.
No rumours about this new sensor have leaked out yet but since the GH has "H" for hybrid in it's name it is by definition a camera that will suit for both video and stills.