More to the point I think you are asking is: is it possible for two sperm to fertilize a single egg and have it survive? Usually when this happens in nature (and I mostly know this about mammals, not reptiles) if this happens it will either kill the embryo, one of the two sets of male-provided DNA will be rejected. It has never been confirmed that twinning could occur from this process.
If, in Ball Pythons, two separately fathered snakes hatched from the same egg, it is most likely that the two separate embryos were encased in a single shell. Not that they arose from a single dual-fathered embryo.
Now to answer you question: Don't know. Seems unlikely though.
-----
Lincoln, NE
0.1 Pastel, 1.0 Pastel het Pied, 0.1 Pied, 0.1 Cinn, 1.0 Black Pewter, 1.1 Normals, 1.0 Thayeri, 0.1 Thayeri X Alterna, 0.1 crazy cat, 1.0 husband