An older traditional style adapter has a steel sleeve around the spring and one snap ring in the starter flange bore. A newer style adapter does not have a steel sleeve around the spring and has two snap rings in the starter mounting flange bore.
The ALE-1013AS brush is perfectly square and is used with the ALU or ALE-3045BS brush holder. The ALE-2013AS brush is slightly rectangular and is used with the ALU or ALE-2045BS brush holder. The brushes are not interchangeable.