In AISC 360-10 table J3.2, for A490X bolts, Fnv is 579 MPa. It was 520 in the 2005 edition of the manual, however.
Here's a reference regarding the 2010 changes: http://msc.aisc.org/globalassets/modern-steel/archives/2011/11/2011v11_a_comparative_look.pdf