They'll know because of the ticket stubs?
/johnny
Read the paragraph again from the article.
The Trilobites that were not on the Ark were in the rolled-up position as they were inundated by the Flood and thus encapsulating them in mud.
The two the were on the Ark would not fit this model and thus could be identified.
Unless of course some huckster evolutionary geologist has already found them and hid or destroyed them as not to destroy that little theory of theirs.