Is it a pure Ameraucana or is it from feed store/hatchery? The problem with the Ameraucana is unless you know the source it's likely just an Easter Egger that was called something it is not. With EE you can have a wide range of egg color so you really don't know what color that rooster is going to pass on as it has yet to lay an egg.
Almost forgot- yes a pure blue layer like Ameraucana crossed with dark egg layer like Marans will result in olive eggs.