A couple of good screening questions to tell the difference....
Ameraucana only lay blue eggs. If your birds lay greenish eggs, they're EE.
Where did you purchase them? Unless it was from a breeder who could specify what color bird you were getting (black, wheaten, etc), they're Easter eggers.
Do they have blue/slate legs and white skin? Green legs or yellow skin mean EE.
Pics would help confirm. Just cause they look like momma doesn't mean they're pure bred, unfortunately.
The egg color chart for Ameraucanas is variable. Shades acceptable are from green to blue and everything in between. Serious breeders generally cull for green layers though. I have a few shades of blue to greenish blue in my flock of BBS Ameraucanas. The egg color chart is available from www.ameraucana.org/clubmerchandise.html