Combines scallop bars

You're right! They go to the rear. Some earlier machines had a heavy angle bolted over this back section to further agitate the straw. Don't remember what they called the dang thing, but both my 1480's had them.

The slope of the angle points toward the rear of the rotor on the scalloped bars. The heavy angles on the rear (not sure of proper IH nomenclature) are usually called kickers. They will help to agitate material in the discharge, and have an angle at the rear which scrapes the rrear angled wall of the discharge chute, but they will also sometimes catch bean vines, since they actually set above the strippers,and prevent them from carrying back quickly.