I honestly don't know the answer. IF you're lucky, one of those girls will lay an olive-colored egg and solve the mystery. On the other hand, my olive egger lays light brown eggs, not remotely any shade of green.
If I'm not mistaken, all Sapphires are hybrids (including my Gems, Olive Egger and Splashes), which means you never quite know what you'll get. In the catalog, my Sapphire Splashes were colorful shades of blue-gray. dark to light. In the real world, both of my girls are totally stark white...