All egg SHELLS are either white or blue, as I understand it. Having said that, some eggs get a "finish coat" of brown pigment just before leaving the hen. If the egg is white, the egg will look some shade of brown, depending how much of that finish coat it gets. It may be very light, like pinkish, or dark like chocolate. If the egg is blue, that finish coat results in a greenish or olive colored egg.
So yes, your two hens, though genetically similar, can each lay her own unique looking egg.
So yes, your two hens, though genetically similar, can each lay her own unique looking egg.