As a follow-up: Any AMC with dual piston calipers - 1970 and prior - used these factory steel spacers to keep the wheel away from the caliper. The caliper casting can rub on the rim unless this factory spacer is used. This applies to both factory and aftermarket wheels.
Would a rim like the AR Torque thrust D need the spacer as well. My understanding is the D stands for disc and the rim has clearance built in. Or do I need to call American Racing?