GM used aluminum full roller tip and roller trunnion 1.6:1 rockers in teh 1996 LT4 engine. The roller trunnion is needed to prevent ball/cup galling above 6000 rpm. The LT4 engine has a fuel shutoff of 6412 rpm.
Even if the geometry is correct, the tip of a rocker does indeed sweep across teh valve stem tip, evr so slightly. Not much at all, but it does, simple geometry/physics.
No need to readjust them.