I stand corrected... I've just found the magazine in question and Duran was 5th. The top 10 were as follows:

1. Sugar Ray Robinson
2. Henry Armstrong
3. Muhammad Ali
4. Joe Louis
5. Roberto Duran
6. Willie Pep
7.Harry Greb
8. Benny Leonard
9. Sugar Ray Leonard
10. Pernell Whitaker

Considering the thread of this topic others of note were....

17. Marvin Hagler
67. Thomas Hearns (?)
68. Wilfred Benitez

Pick the bones out of that lot!!