The bone are ribs and if they are attached to the belly that can easily be separated with a couple strokes of a sharp knife. Ride the blade right down and around the curvature of the bones.
Buying bellies from the local grocer or butcher I have never gotten one with ribs attached. I did recently get a whole Kune Kune that from a co-worker that was quartered so the ribs were still connected to the belly.
The difference having the ribs attached or not all depends on what you are making out of the meat. In all the product I make I would not want the bones attached. But if the price was substantially lower I'd get bellies w/ the ribs and trim them myself. I'd trim and reserve the rib meat for grinding up at a later date when I had gotten enough trimming for sausage/kielbasa and the bones for making stock.
Did the belly look similar to this?
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