I thought you meant featherweight Davey Moore. I doubt Armstrong could do to middleweight Moore what Duran did. Duran was a bigger man than Armstrong, and had considerably more firepower.
Other lightweights that beat Moore? Mosley and Whitaker would beat him. Pac and Oscar too. Can't think of any others.
I think Armstrong would beat Moore. He should've beaten Ceferino Garcia, who was far better than Moore was, and they were of similar size.