Ed - The Hyatt KA11445Z is a tapered roller bearing design, not ball bearing. The Chevy MPC reference I provided above notes that it has "18 rollers" under the earlier differential side bearing Hyatt Part Number HY 11445 Z. KA 11445 Z is a number used by multiple aftermarket manufacturers as a replacement for the original bearings.
Below is a picture from a Chevy Shop Manual showing the differential side gears being tapered rollers (Item 9). Next to this picture is one from The Filling Station of their offered replacement (also a tapered roller bearing and race set) for this bearing application, which also indicates theirs replaces "KA 11445 Z" in the linked description above.
I think your source needs to double check the information they have as these should not be roller bearings.
Edit: Kevin beat me to the post button.
