The datasheets for the similar LM380 and LM390 also show the Zobel network at the IC output. An applications document about the LM380 discusses the important Zobel network that the magazine article ignored.
I recently resurrected a little LM380 amplifier which I made about 30 years ago.
As I was testing it, I noticed on the scope that it was oscillating at some high frequency.
A quick look over the circuit showed that the resistor was missing from the Zobel network. There were holes in the circuit board for it, but no resistor.
I guess that at the time I built it, I did not have a nice low value resistor handy, so I missed it out, saying to myself "I will fit a resistor when I get one".
I guess that I soon forgot about it.
Meanwhile back in the present day, as soon as I fitted a 3.3 Ohm resistor, the oscillation stopped.
So, the moral of this boring tale is: "Don't forget the Zobel network".
JimB