Can a black molly breed with a balloon belly molly?

I'm pretty sure they can. We recently stocked a tank with black mollies and gold balloon mollies; they were all from the same tank in the pet store. A few hours after we put them in our tank, one of the gold balloons had a ton of babies. Five of them made it and are thriving. They seem to be a combination of black and greyish brown and some of them definitely have a balloon shape to them. So we're fairly certain they were a combo of black regular and gold balloons (there were no other kinds of fish in the tank).