ATG Offense versus ATG Defense, Duran fought plenty of fights over the weight at 140 so weight shouldn't be an issue.
I think that Locche doesn't have enough offensive arsenal to outpoint Duran. Duran would be the aggresor for 15 rounds and even if he misses a lot and gets countered occasionaly the amount of his punches throw from all angles catches the judges eyes.
Duran is terrific defensively, while being dynamite offensively. That's the difference here. Locche doesn't have much power and won't be able to keep Duran off. Duran UD
Duran isn't a wildly headhunting Pryor. He'd concentrate on the body, and keep at it while mindful of slipping Locche's counters. It's a punching sport, and Nicolino wouldn't have the necessary output to offset Roberto's hustle. Duran would make sure to put him in a defensive shell and have him stay there. Locche was excellent at smothering body blows, but that wouldn't discourage El Cholo from maintaining his attack there. I think Duran, Arcel and Brown would go in expecting to have it last the distance, and plan accordingly. Do not forget that Ray Arcel was the architect of Peppermint Frazer's dethroning of Locche, and understood Nicolino better than any opposing strategist. Roberto would really be the one to ask about this, but I'd imagine he gave plenty of thought to dealing with Locche in a prospective bout during his reign at 135.
As much as I love Locche, I think Duran would have been a bad matchup for him. Duran's punch variety and tempo would have kept Locche as Duodenum said, in his shell all night..I do think he'd avoid a ko loss and even a knockdown, but it would have been an endless display of Duran's offensive wizardry..a one sided points loss with Locche at least scoring a moral triumph in surviving it all and making it to the end of the 15th round but with precious little offensive output of his own to stave off defeat. It would have been interesting however as the two feint masters would have plied their versions of that nearly lost art.