Rocker arms as in lifter noise? No, I hear a little lifter noise on cold start as well, but that sounds pretty normal to me, comparing it to the usual healthy American V8 cold starting with hydraulic lifters. The racka racka is more like reciprocating sliding steel for a moment, like a clatter rather than a tick. It goes away immediately upon the heads gaining oil pressure, rather than the lifter noise which takes a few seconds longer for the lifters to load up.
1995 E320 Wagon Moonstone Grey/Parchment 106K mi.
2007 E63 AMG Graphite/designo 75K mi