Well I would be surprised because Pyramids (capital P) equals Egyptians, thus pyramids on Mars would imply there were Egyptians on Mars at some point. If however we found some type of general construction on Mars which resembled but was not Earth Egyptian (or Mayan. etc) pyramids, I would be amazed and surprised. I’d be immediately suspicious, because there aren’t other traces of life on Mars, but if they were proven to be of Martian origin then I would accept it as being supporting proof towards the theory that there was once intelligent life on Mars.