There'd be no differance IMO. Tommy would smoke Duran in any matchup thats not P4P. Physically and stylewise he'd always be a nightmare for Duran.
Duran makes his way inside and does enough damage to win a decision. I assume we are talking about the Montreal version of Duran here. I have little doubt he wins. It would be a real fight. It wouldn't be like the one they had at 154 where Duran was clearly past his prime and didn't exactly appear to be in great shape. Duran via UD or late rounds stoppage.