(early A320s, some 737 Classics and 757/767s, etc) that have inertially-driven ADS-B
I have never heard of "inertially-driven" ADS-B. My understanding (albeit that of a layman) is that it requires GPS to "broadcast" the signal to ground stations. There certainly are older aircraft that are satisfying ADS-B requirements, but I understood they had to be retrofitted with GPS.