They could say they were HIFI which meant they were a little better than the rest. Plus, playing the new hi-fi records of the time.
Come to think of it, for a station to claim that they were “hi-fi” because they played the new “hi-fi” microgroove records is not that different from stations in the early 1990s that claimed they were “digital” because they played CDs. I am still interested in what “hi-fi” meant in KHFS’s context. Did their custom-built transmitter have lower distortion and a wider frequency response than the 1kW transmitters that RCA, Gates, et al were making back then?
On a somewhat related note, at the Puyallup hamfest, I picked up a Hickock swept-frequency alignment generator intended for broadcast-band receivers. It generates output on either 455 or 1000 kHz. The maximum deviation is on the order of +/-15 kHz. I haven’t fired it up yet, and I was told that it might need some work (such as the replacement of dead electrolytic capacitors). So, there were some AM tuners back then that needed more than the single-frequency (tune for maximum response at 455 kHz) IF alignment. I suspect that these high-fidelity tuners were niche-market items, though.