As people have noted, they won't ever build the *exact* models they fleshed all the way out for WRE. As people have noted, they designed WRE for Orlando, but they did have a model of Western Expedition on display on Main Street in Disneyland decades ago.
Frontierland is being eyed for expansion, and it doesn't really have anything in the way of "cowboys, indians and bankrobbers" in terms of an attraction. If they do put in the western river ride, it will have totally different scenes, totally different ride mechanism, and perhaps some influences of Mexican culture given how some of the old west was once part of Mexico. It could offer something totally new not yet seen in a Disney park.
And being totally different, there would be no reason to call it "Western River Expedition". Maybe they could call it "The Long Ranger's Adventure", or ,"The Long Ranger River Run", or something like that . . .