This variety was gone, for 2000 years. The origin date was pretty firmly established. 'IMHO' is worth much less than a measurement, which indicated from 2200 to 1800 years.
"IMHO" there are a lot of well known problems with carbone datation. You can read about it in scientific journals and make your own opinion.
Any measurement can have errors of methodology, and a wrong measurement does not have any value. Don't worship numbers just because they seem fancy or fit with a narrative. They are just that, a number.
Without a genetical analysis we can not know if a plant variety is lost, or just forgotten, or a clone of a extant variety buried ten years ago. Show me the analysis before to start talking abour old ruins, caravans and lost cities.
Would be like finding a californian dwarf elephant again.