The RG96 has a hammer made of zinc alloy - bad enough - but the bolt head is very wide so it won't have too big an effect on the massive hammer.
Mike
P.S. - The biggest RÖHM pistol, called "Model 725" (usually they are always named RG...), for example, has a hammer made of zinc alloy with a round steel inlet because the bolt's head on that gun is much slimmer than in the RG96 and would cause a dent in the hammer's surface after some time.