Thanks Grumpy, the second link basically puts and end to my questions:
If Harvey Gerst Specifies it as 60W RMS max, then that is what is.
Hopefully Harvey made sure not to have considerable Hang-Time at the higher power test levels that would blow a speaker way before it's actual rating. We will never know.
So I will treat any Original Cone D120F as 60Wrms continuous and the D120F with E120 coil reconed as 100W rms, the latter which would be accurate if the K120 and the D120F uses the exact same magnet.
Power specifications for the F series were nominally 35 to about 60
Watts. How did I arrive at these figures? Pretty simple, I played guitar
and bass through them and kept increasing the power till they blew. Then
I downrated them from the power that fried them. Pretty hi-tech, huh? It
seemed to work pretty well (of course we didn’t have synth players back
then).