Well, is having black eyes a dominant or recessive gene? What about the color white? Are they linked genes? How tightly are they linked? Are there any known genetic quirks? If you say you understand gerbil genetics so well, you should know the answers to these questions. Hence, you could answer your own question.

ETA: What a gerbil is phenotypically probably isn't what it is genetically. So, theoretically, once you've found the "correct" pair that will give you black eyed white pups, you'll have to dig deep and/or test mate your parent gerbils to find their true genetic history.