Never heard of an engine knocking at that high of an RPM. I would think that the cylinder charge turbulence, lack of time for heating of unburned fuel, and lack of time for excessive pressure build up would eliminate knock before RPMs got that high.
If its detonation, it would occur at a lot lower rpm than that I believe. If your mechanical advance is all in at say 2400rpm, thats closer to where the rpm knocking would start, probably less, then drop off as rpm increased.
I'm no expert.JMO