Junior was the better fighter overall and should win but he wasn't as good at 126 as he was at 122. I think Jones would be winning the fight until Kelley lands a desperation bomb. Once Junior gets hurt he falls apart and Kelley stops him.
If we're talking about Jones in '97 when he was being discussed for a fight with Hamed, then I think he beats Kelley. The Jones that started seriously campaigning at FW post-Morales was past his best though.