Roy at 160lbs had blinding hand speed and thudding power. GGG would struggle to find him, and would eat a lot of leather in the process. RJ UD.
Styles make fights, and GGG's ability to cut the ring off and relentless, yet patient pressure is going to get to Jones eventually. Golovkin knocks him out.
GGG by KO. Jones wouldn't be able to handle the power and he would get hit. Roy's accomplishment at Middleweight was beating green Hopkins for a meaningless trinket vacant belt. That is it.