My wife kept the male back many years ago and yes he had a few black markings down the mid section of the belly which my wife automatically coined it a black belly. The female we bred it to was just a grazianni x bell pastel that was not het for anything. So we ended up clearing out all the ball pythons to focus more on dart frogs and other animals in the past month or so. We had the clutch here cooking and they hatched except one that pipped but did not crawl out unfortunately. Two of the offspring do have a few black flecks to the belly but not as much as the blackbellies I have seen for sale last season I believe. The other babies were a regular pastel and a normal with not black flecking. Take a gander at the pics below and let me know what ya'll think about the dead one(died literally a day or two before the others crawled out) and the rest of the clutch. sorry for so long.
Below is a link to all of the snakes via photobucket. click and enlarge pics to see title/description of each baby.
PHOTOBUCKET GALLERY