I think Cooper probably died in the jump, but cannot pretend it's beyond reasonable doubt. What I would say is that if he died then he likely would have been reported missing if he were in regular employment at a place like Boeing. Though he could have been an ex employee.
This find is definitely of interest, but let's everyone not jump to conclusions about him working for Boeing. Im certain other places also used these rare earth elements.
SST program lost funding in March of 1971. Layoff???
Passenger version of a cargo plane (USAF CX-HLS competition) saved Boeing—designation 747. Lockheed had won the military contract with the C-5 Galaxy. Everyone expected passenger service to be by SST, until the sonic boom issue over land derailed even the Concorde which was already in flight testing 1969.
Maybe he bought the tie at goodwill?