Maybe. Mayhaps he would. I'd pick prime Duran by KO for sure. That said, Manny is pretty far past prime and is a little bit smaller than Duran if I'm not mistaken. Now that I'm thinking about it, I'd pick Duran to KO any version of Manny as well. You like to make threads; go make that one. That said, Manny has accomplished quite alot in his career and were he to manage to convincingly beat Spence at this point, it might not be too much to consider him keeping company with such as Hands of Stone imo.
The one that beat Cotto and caused Floyd to post pone their fight for 5 years. Remember Kentucky Floyd chicken?