These are genuine NOS Sanken transistors. There are a lot of fake Sankens
out there. One of the ways to tell if a component is Genuine ore fake, is to weigh the component. Fake ones (f.e. Chinese Copies) mostly weight around 15 grams. The Real ones around 18 grams. This is due to the difference in die size.
For more info on fake vs genuine google for 'sanken fake 2sc3858'.