I have never heard of a roller cam being wiped out upon startup. Yesterday at the track a guy was telling me about his experience of tearing down his new built engine to clean out the metal. I myself have did the same over the years. I'd look at the cost of pulling the engine and tear down and rebuild in your decision . Cheaper ,not that anything is nowadays as they say is not always the best way to go. From running flat tappet cams from the start in the 60's I now have a roller kit on the shelf for the next rebuild.