Were the amp wattage ratings different in the 60's than they are today?

Yes because there has never been a set standard for rating amplifiers. Back then they used "real world" measuring techniques like true RMS power right before clipping while operating the full frequency bandwidth(20Hz-20kHz) and at a low total harmonic distortion(THD) like 1%. Back then audio equipment was better quality and was either made in the U.S.A., Japan, or Europe. Now almost everything is cheap quality junk mass produced in China. And since there's no set standard for wattage ratings manufacturers make whatever claims they want in order to boost sales. Today amplifier X might be able to produce 1000 watts of power but probably at a frequency that is above and beyond a human's hearing range while at 10% THD or more and at a very low impedance and only for a split second. When selecting an amplifier pay attention to the RMS watts. Don't mind the peak, max, or music power ratings. Also keep in mind that there are different classes of amplifier design. Class A,B,AB, and D. Each has it's advantages and disadvantages.