Right now I doubt their color will give much away. You'll need to wait likely 4 more weeks for quacks from the girls. Though I had 1 that seemingly took forever. To this day she still has a raspy quack.
A pastel shouldn't have a dark bill and should be colored like a gray, but with a lighter blue hue. Correct me if I'm wrong @WVduckchick, and @shawluvsbirds .
They do all go through an awkward disproportionate stage. That's why good breeders typically only sell adults as exhibition quality - you can't really tell what you've got until they are more mature and leveled out in growth.
You can get both pet and breeder quality from Exhibition quality...