2SD582 / 2SB612 (TO3)

I recently found two pairs of those in my box of forgotten transistors. They seem to be original, at least I have got them as spares way back in time (35y).

Does anyone know more of these? I guess they are from Toshiba, but there seems to be no more data sheet available. I think they should give a nice amplifier in some old style of circuit.