Thats a very nice lesser and could well turn out to be a pastel lesser, but like the others have stated, it has to be bred out or its just a lesser. Talk to the breeder and see if there are any chances. I have seen some stellar lessers that were really bright in person but I have no pictures for you to compare. If she turns out to be the single gene you really have yourself great snake. Thats a girl any collection could be proud of!
My pastel lesser as a baby:
http://ball-pythons.net/gallery/file...0/dsc_0008.jpg
Same girl about 500 grams bigger:
http://ball-pythons.net/gallery/file...0/img_1409.jpg