Q: Is this the same as part 605-89 which is a cork gasket ?
A: No. This cork gasket was used on the interior of the vehicle. Argo found over the years that the chain lube and grease build up on this gasket deteriorated the material and would loosen the flange and nuts causing per-mature bearing failure.
Argo has since recommended not using any cork gasket on the interior of the vehicle and to place the flanges directly on the frame as all newer model feature. Making this change when replacing bearings is recommended to increase bearing life.