those are "house numbers". they were probably made under contract for a manufacturer. RCA and Zenith used to have parts with a similar number format. unless you find an ECG or SK book from the 70's, you're unlikely to figure out what they are. the best method would be to test them on a curve tracer, and run Ft tests, capacitance tests,to get their specs, and see what they match. they are most likely common motorola transistors, but just re-named to force repair techs to buy the parts from the mfr of whatever they were used in (house numbers were common among TV manufacturers)
a good example of house numbers is the following list from Peavey (a guitar and PA amplifier manufacturer)