From a feed store, almost always (dare I say *always*?), it is an Easter Egger if the sign says Ameraucana.
These have green legs, but not the usual beard and muff showing the Ameraucana blood that should be in their background.
Here's a good article to tell the difference.
The article LofMc posted is a very good one. I think you'll find out for sure when some of the pullets start laying. If they lay different colour eggs instead of just blue, it could mean they're EEs. I'm not sure what I'd do about the cockerels, maybe wait and see any characteristics of EE in them. Then again, a genetic test would be most helpful here.
You can tell these are definitely not Ameraucanas now without waiting for egg color to appear.
Ameraucana chicks have fluffy cheeks for the beard/muff that will come later. They should have pea combs (can't see in photos). Also they should have slate/grey legs (sometimes willow with certain colors). Ameraucanas also come in only 8 standard colors. Of those colors, only Silver produces a chipmunk chick, but its tones are silver, black and white. These chicks show a wild type pattern with brown that is not going to produce a Silver Ameraucana but what typically becomes the partridge of an EE. You can see what I mean here: http://www.ameraucana.org/gallery.html
And yes, it makes a difference if you paid $$ for a true Ameraucana but got an EE. (Fortunately feed stores usually charge pretty cheap prices for their chicks no matter what the "breed.") It is unfortunate that feed stores still propagate the falsehood of Americana as it confuses matters. Usually (not always) they let people know the hens may lay brown, green, or blue eggs. If not, it is misinformation if people buy them thinking they are guaranteed (or even likely) to have blue eggs.
Green egg is the color of an EE, so if you get green it will be an EE, but you could get blue and still have an EE. Green only happens if the other parent is a brown layer. Blue is dominant (over white, the only other base color for the shell), and blue mated with a brown layer produces a blue shell with a brown wash for the color green. (Crack open a brown egg and you'll see what I mean...a white shell with a brown wash). If the blue was mated with a white layer, it will produce a blue egg, not green, and yet still be an EE as it is not a true Ameraucana and will not carry 2 blue genes. (That means it makes a huge difference in likelihood of getting a colored layer if an EE roo was used over a hen of another breed as the roo may not have gotten a blue gene to pass along. If he did get the one blue gene possible in the hybrid, he will produce 50% green/blue or 50% brown/white layers depending upon what the mother lays. You won't know what you've got in your roo until his daughters begin to lay).
I am suspicious as these chicks are not fluffy cheeked which means that Ameraucana blood may be pretty far back(ie an EE roo was used) such that blue genes are less likely to appear.
But if you are happy with them, don't mind they'll be like a box of chocolates, you're not going to be sure what you'll get, they are usually well mannered birds and good layers and will be a fun flock.
EE as well.