That's true of hatchery ameraucanas but it's also true of hatchery araucanas. The ameraucana.org site states:
As far as can be determined no tufted-rumpless fowl were used to create any of the eight recognized varieties of Ameraucanas. Ameraucana bantams and Ameraucana large fowl are standard breeds. They have specific requirements with regard to shape, weights, coloring, comb, earlobes, and so on.
All araucanas are rumpless and have ear tufts or they aren't araucanas. The ameraucana is it's own distinct breed with it's own characteristics. Easter Eggers are a cross of either with other breeds of chickens.
All true Araucanas do not have ear tufts and are rumpless. I bought chicks last year from a true araucana breeder and was told not all would have tufts and be rumpless. But they are still true araucanas.