I think every 486 I ever saw at least had a heatsink, and a few had heatsink fans.That's true all older processor haven't any cooler or just a radiator but take probably less power too due to slower clock. 486 DX2 = 6.3W maximum power listed on cpu-world that was my first computer/processor
I don't think my 386 even had a heatsink, though.
I do remember one Pentium (maybe 166, 200, or even 233 MMX) in a Compaq desktop that had a passive heatsink.
Are you sure it's not just the bare die he's looking at? That how it seems to me, but I did not listen to the audio.That's permit to have an X-Ray view when CPU heating it's just amazing