Zinc and Phosphorus are additives that help cut down on break-in wear. This is extremely important for flat tappet cams....not so much for roller cams. LOTS of people, even professional engine builders that advertise on this forum are having trouble with flat tappet cam break-in due to the change of
oil formulations over the past couple of years. It's almost a "cross your fingers" type deal now. If a cam goes flat, you've lost a cam and a set of lifters. If it's a bad case, you're in for a rebuild as the metal will kill the bearings and scar the crankshaft journals.
If you've made it this far without wiping the lobes off, consider yourself lucky....but I would be changing oils and throwing in a can of EOS just for reassurance.