The firearms reference table is continuously reviewed and updated. As the staff who build the reference table become aware of new firearms, they're added to the table. If there are new variations of existing models, those are added. If it turns out there is some kind of missing or erroneous information in an FRT record, and that becomes known, then there's a process for ensuring that it is corrected.
The firearms reference table process is very much akin to the ISO process, even though it's not ISO-certified. It follows a similar process in that one researcher will be responsible for collecting the information to either create or update an FRT record concerning a particular firearm. Then, a second, independent quality assurance analyst will review that information to ensure that it is accurate and complete before the record is actually published.