Have you measured it ?
Looks like a typical TO-3 package (should have two pins on the bottom offset from center).
This is most likely just a power transistor.
I would happily throw a pair of these into a quasi-complementary audio output stage delivering 60W without knowing anymore than my above guesses. Stability would be trial-and-error but really not at all difficult.
You might try contacting the maker of the gear they came from for schematic and tech data, and you might contact ST and see if they can shed any light on those house numbers.
That logo looks familiar but I can't place it. Notice the bottom numbers are the same as the others but the top sequence is different - possible production related numbers?