You can see it here:
The version of Preach My Gospel on Gospel Library still features the Christ at Chichen Itza painting, though. so it's probably just a quirk of the lds.org version.
Still, at least missionaries who study Preach My Gospel aren't being taught M2C when they use the version on lds.org.
It's probably not an indication of anything significant, but at least there's one Church manual on lds.org that doesn't overtly teach M2C.
The .pdf version still has the Chichen Itza painting, and probably the printed version will as well.
Sadly, the new version still doesn't quote D&C 28:8. We don't expect that to change because the Correlation Department doesn't want members of the Church--especially not missionaries--to ponder why the Lord identified the Indians in New York as Lamanites. That's why the Church History Museum has changed the narrative into a mission to the Indians, as we've discussed here:
"And now, behold, I say unto you that you shall go unto the Lamanites and preach my gospel unto them."