If you want to see the FAA's position this is the complete document. To the right side of this webpage you will find a link to comment on this IFR (interim final rule). Comment period is only open for roughly two more weeks. I strongly encourage every modeler to participate.
After reading this document it looks like the FAA believes the registration of all model aircraft is not contrary to the provisions of Public Law 112-95 Section 336.
If you read the 336 bit alone it doesn't present the full story, nor the current position of the FAA. I now understand why the AMA is fighting the FAA.
https://www.federalregister.gov/arti...anned-aircraft