I'm reading that JB has or is about to sign 3 EOs regarding uppers, gunsmithing and long barrel pistols. Now all pistols with a brace fall under the National Firearms Act (requiring registration and a $200 fee with BATF). All uppers sold after 8/24/22 will require serial numbers. Lastly, gunsmiths cannot work on "ghost guns" without adding serial numbers for which they must file with the BATF.
https://www.thedenverchannel.com/ne...ing-brace-for-pistols-citing-boulder-shooting
https://www.thedenverchannel.com/ne...ing-brace-for-pistols-citing-boulder-shooting