What I suggest is combing through NAMUS case files to see if GD was reported missing. Since gd's DNA and prints are already in the system, this should whittle down the possible matches. Unfortunately, Namus does not have an advanced search where you can exclude possible matches with available DNA and fingerprints. Since GD was no older than 25, we can go through all missing persons cases from 1970 until 1995 with no DNA or fingerprints on file. If he is in Namus, then that would be the best way to find him.