And the likelihood of any of it being Cooper's DNA is probably low. That tie was picked up by agents in Reno, taken to a Penney's, sent to the Crime Lab, sent back to Vegas, then sent again to Crime Lab in 72, sent back to Vegas, then sent to LA in 74, then sent back to Vegas, then sent to Seattle in the 90's, then sent to Crime Lab in 2001, sent back to Seattle, etc.
It has seen some miles and numerous hands since NORJAK.