Those splines are part of the hub assembly which slides into the bearing. There are no splines on the old bearing.
I changed mine by 1st pressing the hub off the bearing. Pressed it from the backside of the knuckle. After the hub is removed, pry off the front C-clip and press the bearing off the knuckle from the backside as well.
Reassemble in reverse order. Use antiseize compound on bearing OD, ID and the hub splines.
