its impossible for an old coin to be not detected but as far as i know all old coins are already known how good or bad they are . it was the new coins that are the real undetected because they are anyway .

 everything here is a gamble but  if i will rate hodl i will say that it was the less risky way of gambling but not knowing what to do if if your going to sell or hold is more risky because you are likely going to sell afterwards .