Same issue different type of gun.
Not exactly the same as the OP's reply. In that reply they say a kit can be converted back and forth. Closer to the precedent set in the SCOTUS ruling in the Thompson case, and something that may actually stand up to review.
Can you point to another SCOTUS case deciding on the legality of something under the law which did not set precedent in any similar situations? It would be impossible for the case to only apply to the Thompson kit and no other firearms.
The SCOTUS decisions over hundreds of years have not worked that way. Yet they do in the Thompson case?
No.
The issue at hand was the application of the law, the same law that went through the appeals process. Then determining how that applied in the Thompson case. Which would then set precedent for the application of the law in the future.
However the most recent letter seems to have switched thier legal position that it applies to kits specifically.
Something I still don't believe is true, the SCOTUS was addressing how the NFA's SBR portion related to all pistols.
Yet the ATF could at least plead ignorance and play dumb on the new view that it only applies to kits in general.
They could not realistically hold that a SCOTUS decision set no legal precedent and only applied to a specific kit when the case was about the law in question and how it applied to such a kit, not the kit itself.
The court specifically addressed customers having both a pistol and a rifle in the same kit, and the utility of such a product.