Color should start showing up in about 6 weeks after hatching, maybe a little sooner or later. Mine that hatched were all Ivory or Purple so far. I didn't have any blues from these guys yet, pretty sure those will come from the darker purple couples in the other tank that just hatched. Color is still coming in on a few of the smaller ones and they are about 9ish weeks old now. Even 4 months after they are hatched they are still prone to change and develop their color a bit more densely so be aware that any you get MAY indeed not have the color fully developed and I am positive that the extremely shiny light purple silver color that my babies are showing now will NOT stay the same as they grow (wish it would) yours should show the same color as well, as pretty as it is I expect it to darken and as they grow to get their stripes.
Even as babies they are super, super messy so keep a close eye as they start to grow so they don't ruin your substrate or water quality. The more plants you have stuffed in with them in the substrate to eat the waste the better as they get a little bigger.
As they grow some will grow faster then others so drop food in a couple different spots in the tanks as the bigger snails will hog the food and not let the tiny guys eat.
They need to be shipped in water so mailing in an envelope probably wouldn't be the best thing to do, as the baggy with water will get smooshed and more than likely ruin the envelope and kill the snails inside.