Ameraucanas are a pure breed. They are considered a rare breed and they are expensive. Easter Eggers are a multigenerational Ameraucana hybrid and very frequently missold as pure Ameraucanas.
It's way too young to tell with any certainty. Try back at 8-10 weeks for a more accurate response. For now, I'd guess the RIR is a cockerel and the Easter Egger (it's an EE, not an Ameraucana) is a pullet.