No mythology involved here.The car manufacturers and the oil producers used to say the same thing back when the synth's were first introduced enmass.
These are 80's style engines with 80's build technology.
The newer engines are all roller[hipo anyway].
The need for proper cam breakin is not there like it used to be.
Cams do tend to break rather quickly[sometimes not],but there is still metal to metal seating that goes on for the first couple thousand miles or so.
Remember again,these engines are an 80's design.
Besides,what can it hurt?