Even on the original there was a sleeve . The rubber touching the sides of the brackets is irrelevant and had no function. As long as the bushing it tight in the eye and the inner bushing is squeezed tight within the mount you are fine.
IMO regarding your last two comments, you are making two contradictory statements, the last one being mostly the correct one, just to be clear for others.
All to mean, the leaf should not contact the mounting bracket, tightly squeezed rubber bushing prevents that contact in all but the most brutal impacts.
