Please make sure you are listing your items appropriately.
On April 11, 2022, the Attorney General signed ATF final rule 2021R-05F, Definition of “Frame or Receiver” and Identification of Firearms. The goal of the final rule is to ensure the proper marking, recordkeeping, and traceability of all firearms manufactured, imported, acquired and disposed by federal firearms licensees.
The rule will go into effect August 24, 2022; 120 days from the date of publication in the Federal Register.
Details can be found here:
Definition of “Frame or Receiver” and Identification of Firearms
Overview of Final Rule 2021R-05F Definition of “Frame or Receiver” and Identification of Firearms