I would sell them for at least $600 if they where that large. Keep in mind though that you may not get "paperwork" on animals that are not 100% hets. I would not let the presence or lack of paper work affect your decision. The seller should have some references and/or you could ask to see picks of the whole clutch so you can see that axanthics where produced.

I hope if you decide to buy them you get lucky!