Ah, the top one is where the diagram up-thread came from. Completely execrable as one would say in polite company.
The second one shows it now has grown discrete output Darlingtons and an emitter pulldown
Oh, look, it's got a proper adjustable Vbe multiplier AND a pair of current limiter transistors. Ooh and split rail power supply and DC coupled output. AND a diff pair input stage.
This isn't the same amplifier! Still not thrilling, but it's lost a few schoolboy howlers. I see they still bootstrap the collector load of the voltage amplifier stage. And like the first one, it still lacks the series element of the zobel arrangement in the output. I guess they didn't know what that part did. Don't put this one anywhere near silly speaker cable
Now, what about the third one?
Looks rather like the second one... still no series Zobel network, just the shunt part. No wild differences. Still no catching diodes. Still not much of a clue, by the evidence.
So the first one is a bit of a joke. The second and third ones are nothing special.
They got praised to the skies in print? Ye gods and little fishes! Well, the first one ought to have offered a lot of 'character'
David