Don't remember anything about Roger Osborne being linked with City, but I can remember Southampton winning the cup in 1976, beating Man Utd 1-0 with a late goal scored by Bobby Stokes.
Early in the 1976/77 season, City played Southampton at Ninian Park in the Football Combination reserves league. I think it may well have been the first game of that campaign. My father took me down there and I can remember being amazed that the man who'd scored the winning goal at Wembley a few months earlier was playing up front for the Saints at Ninian in front of a crowd of a couple of hundred. Of course, the FA Cup final was a much bigger deal back then. For a kid like me (I was nine at the time), it inconceivable that a superstar like Stokes should be playing our reserves.