The heat treating process is only done on the tip otherwise the rocker arm would be too brittle and crack, some engines have chrome plating on the tips because this method is cheaper and easier to do on mass than hard facing, but either way whatever these engines have it is flaking/wearing off and the arm requires replacing, and nicks or marks on the cam should be polished off with some fine emery tape, I usually use old 480 grit tape, stuff that is half worn out, mainly because we have heaps of it laying around the shop from the crank linisher.