The Vietnam Black hybrid from Anonymous is alive... original Da Lat, Da Nang, Nah Trang or different landraces is another thing.
Vietnam was never a big Cannabis producer, many of the weed was imported from the neighbouring Laos and Cambodia due to the strict laws and prosecution. The DEA started operating in Thailand and SE Asia decades ago, when the Golden Triangle oppium bussines was at its best. Aerial spraying was happening not only in Jamaica, Mexico and Colombia, also in SE Asia.
Vietnamese growers have moved into indoor growing a long time ago. Now it's the Kush and the autoflowering strains what they crave. The Vietnamese mafia buy seeds online and sell them to the growers.
I doubt there are many old landraces left unhybridized... it's something global nowadays, from Mexico, to Colombia, Jamaica, Vietnam, South Africa, Indonesia and even the India and Nepal, the birthplace of Cannabis culture. Original landraces are dissapearing thanks to the prosecution. Hybrids and western genetics are demanded everywhere, since they are much faster, more potent and productive. It's all advantages for the locals.
Reports of hyrids are happening even in Aceh Indonesia, one of the most remote and poor Cannabis produciong countries.