Here's some evidence for Upper Guk at least:
http://www.eqclerics.org/forums/arch....php/t-41.html
"Viscera
01-06-2000, 13:36
At L52, everything still aggroes me that did at L34. Gaz knights will occasionally aggro, along with all tons. However, sometimes you can run by them quickly enough so that the aggro check doesn't happen when you are n aggro range (which I think by experience may be every 2 seconds or so)."