No its not how its supposed to work but several trigger packs are serialized, its not always the weapon. I read this as the braces are the NFA item, not the whole gun.
Maybe i read it wrong or saw what I wanted to see
Are you sure ? They are declaring the brace to be an NFA item. Thats how I read it, if you read it differently, show me.
Pretty clear if you read the FAQs (grabbing a few here)
6. WHAT ARE THE COMPLIANCE OPTIONS FOR AN INDIVIDUAL (NON-LICENSEE) IN POSSESSION OF A FIREARM EQUIPPED WITH A “STABILIZING BRACE,” WHICH IS A SHORT-BARRELED RIFLE (SBR), AFTER THE EFFECTIVE DATE OF THE FINAL RULE? • Submit through the eForms system an Application to Make and Register a Firearm, ATF Form 1 (EForm 1) within 120-days from the date of publication in the Federal Register. • Permanently remove or alter the “stabilizing brace” so that it cannot be reattached and thereby removing it from regulation as a “firearm” under the NFA. • Remove the short barrel and attach a 16-inch or longer rifled barrel to the firearm thus removing it from the provisions of the NFA. • Turn the firearm into your local ATF office. • Destroy the firearm. For more information go to How to Properly Destroy Firearms | Bureau of Alcohol, Tobacco, Firearms and Explosives (atf.gov).
ONCE THE FIREARM IS REGISTERED AS A SHORT-BARRELED RIFLE (SBR) CAN I REMOVE/CHANGE THE “STABILIZING BRACE” OR ATTACH AN ITEM MARKETED AS A STOCK? IF SO, AM I REQUIRED TO NOTIFY ATF IN ADVANCE? • Yes, the firearm is registered as an SBR, and you can change out the “brace” device or stock for a different brace or stock. You do not need to contact ATF/NFA because changing the brace/stock 5 does not change the configuration of the SBR. However, if the length of the firearm has changed you will need to notify the NFA Division.
15. IF I ATTACHED MY “STABILIZING BRACE” ON A RIFLE WITH A 16” BARREL, WILL THE FIREARM FALL WITHIN THE PURVIEW OF THE NFA? • Generally, no. A rifle with a barrel (rifled) of at least 16 inches would not be an SBR under the NFA regardless of whether it incorporates a “stabilizing brace” or traditional shoulder stock. Note, the firearm would need to retain an overall length of at least 26 inches and not fall into other NFA categories. Firearms with an attached “brace” device may be submitted to FATD for a determination.
16. CAN I LEGALLY SELL MY “STABILIZING BRACE” TO SOMEONE WHO MAY BE INTERESTED IN MAKING A SHORT-BARRELED RIFLE (SBR)? EVEN AFTER THE TAX FORBEARANCE PERIOD TERMINATES? • ATF does not regulate the sale of firearm accessories.
17. IS THE “STABILIZING BRACE,” BY ITSELF, AN ITEM THAT REQUIRES REGISTRATION UNDER NFA? • No, a “stabilizing brace” is an accessory and ATF does not regulate accessories. However, a firearm equipped with a “stabilizing brace” may be subject to registration if it is an SBR because it is “designed, redesigned, made or remade, and intended to be fired from the shoulder,” as described by the amended definition of “rifle” in the Code of Federal Regulations and has a barrel(s) of less than 16 inches or an overall length of less than 26 inches.
All they did was say that except within the very small category of firearms (which are extremely vague) a brace=a stock. If you have a brace on something with less than a 16" barrel you are currently a felon in violation of the NFA. However if you do your civic duty and register it within 120 days they will not file charges (maybe).
So you can remove the brace, replace the barrel, register it or destroy it. You can't sell it (since its an unlicensed SBR). There is some guidance that suggests as soon as you file the registration you can swap it for a stock, since in their eyes you are already in possession of an unregistered SBR.