These probably date to the early-mid 1970s, if dating by the materials they were stored with is correct. Most semiconductor is somewhat sensitive to light (silicon solar cells, for example.) Light biases the junction within, and allows it to conduct. They're cool because they're a TO-92 case transistor, and if you could put them in a completely light-free room, they'd probably work (poorly) as regular transistors. There was a bunch of other interesting things with these devices, including some stuff that appears to have been meant for detecting radiation-emission devices. That's just a guess however, the person that had these is long dead so I can't ask.