Right and Left.
Plus the early stanchion has a 'notch' or incomplete trailing edge on the rear, which provided weak support. Don't know exact date in production for change, likely before Jan 1926 had this early type.
photo shows early, driver side Left, with 'notch' look.
The later has no rear edge notch, the trailing edge is flared to the rear to complete the strength needed.
photo shows later, passenger side with flared trailing edge.