The change in pitch from 50Hz to 48.8Hz was 0.4 semitones.
12 * ln 50 / ln 2 = 67.7
12 * ln 48.8 / ln 2 = 67.3
This is kinda unrelated (it involved a line frequency slowdown from 60 Hz to 51 Hz), but I always found this radio recording of the US northeast blackout of 1965[0] fascinating as the DJ is grappling with records/tape cartridges slowing down and lights dimming live on the air https://www.musicradio77.com/images/ing11-9-65blackout.mp3
If I listen carefully, I can tell the difference between 48 and 50hz using a sine generator (although it's very subtle), so I'd guess that you possibly could.
Probably, although you are more likely to hear the 3000Hz to 2880Hz change in the generator RPM than the 50 to 48.8 change in the output.