I think the caps were cast that way, not panto'd. The flat plates on trek seat stays were stamped. It's not that easy to fake such things, but I guess if it was actually machined instead of cast that would be a clue that it was fake. If someone could adequately fake a Colnago frame it would be a shame they didn't just make something under their own name. Usually fakes are somewhat crude, so that gives it away.