The first mention of an upgraded camera sensor was in F(x)tec's February 2021 update on IGG, the same update in which the SD662 chipset was revealed.
F(x)tec appear to have come through with this. The first image of the new sensor was in their June 2021 update.
Mentioned again in their August 2021 update, and most recently in their October 2021 update:
As final assembly is beginning now, I assume it's safe to say they have all the sensors now, and they will be included with the Pro1 X.