Check their leg color. Is is green? Yellow? If their legs are anything but slate grey w/white soles or black w/white soles, they're Easter Eggers.
Check their plumage color. Does it look exactly like any of the accepted Ameraucana colors? If there's a shred of doubt, it is an Easter Egger.
Also - chances are if you're curious about your birds being Ameraucana/EE, or you spelled the name wrong, or you got them from a feedstore or hatchery, they're Easter Eggers.
Still, EE's are just as wonderful and lay colored eggs.