Yes, another person in the thread found that already. The provisions in 302a don't originate from either of the statutes you cited, but rather from Public Law 90-379, enacted by Congress in 1968: see https://www.congress.gov/bill/90th-congress/house-bill/14910....
It sounds like it will be up to the courts in this case to determine if these specific FCC regulations are actually made pursuant to the purpose of that section, and whether operating a marketplace within which others are offering radio equipment for sale can be interpreted as you yourself offering that equipment for sale.