I'm a big newbie as well but it does seem that heterozygous animals do have pattern aberrances. They also seem to have a lighter color as well.
Some animals it's nothing specific but more or less just an overall look they have. Something just out of the ordinary almost like "It's hidding something"..lol
This is a group shot of the clutch from which Jas's snake was produced. A Het to Het breeding. I got 1.1 Homozygous lavenders and 1.2 66% possible het lavenders. Chances are 2 of the 3 66% possible hets are going to prove out to be true hets. Well just looking at the little 66%ers 2 of them have pattern aberrances and are also a shade lighter in color, my guess is those are the true hets.
Of course I'll be keeping both 66%er girls because after all, it is just a guess..