This would be a very long shot but how about registering then logging your flight on the following site and then use its search facility to see if anyone else has logged your particular Flight Number ....
FlightMemory - Where your memories fly! - Create your personal Flight Memory and keep track of where you've flown!
Both my son and I have logged all our flights (dating from 1982) on this site so it might be possible that someone could date back to 1963 ...!
Best of luck