Legendary does not make them, and the guy on ebay is selling the foams that look like those I bought. His advertisement "1970 1971 BARRACUDA CHALLENGER CHARGER CORONET DART DUSTER DEMON SATELLITE GTX SUPER BEE ROADRUNNER BUCKET SEAT FOAM BUN - This part is compatible with 10 vehicle(s)"
For reference purposes, following are pictures of both seats. The Charger seat is narrower at the top and has deeper wings that snug into the side of your body. The seat foams required for each seat are clearly different, yet those who manufacture them lump all the B bodies of that vintage together.
Anyhow, if you currently require seat foams for your 1970 Charger, be prepared to do some modifications to these foams to get them to fit. Who knows, someone might come out with a purpose built foam next month.