NAICS codes in Public Firm Firmographic information

Hi team

I'm wondering how the NAICS code is generated in the Public Firm Firmographic data as for one company Lockheed Martin I'm seeing it's NAICS code as Jewelry and Silverware Manufacturing when they are a defense contractor. Appreciate this is one line in the data! so could be lots of reasons but would be good to understand why this NAICS code is given if it's possible other companies have a similar issue.

Thanks

Niall