This is an intriguing matchup and I salute you for sharing it. Hernandez was good at using distance and could fight going backwards. Consider the Azumah Nelson fight. On that basis, I pick Hernandez by decision.
For all his athleticism, Gamboa had ZERO skill and a poor chin. Not much of a ring IQ either. He was able to overwhelm cats at 126 with his handspeed and power alone, but that shit ain't gonna cut it against Hernandez. Hernandez wasn't as fast, but he was the much better technical boxer and he was tough as nails and a better thinker. I'd take Hernandez by decision. Gamboa's speed troubles him early, but Hernandez's skill takes over down the stretch. Hernandez wasn't a big puncher, but he had deceptive power, and he probably hurts/drops Gamboa at some point.
If you look at the two guys that really dominated Hernandez, they both were fast like Gamboa but both were also tremendous boxers (especially Floyd) Gamboa’s speed is in that class and he certainly had pop but he’s 5’5 going against a 5’11 guy ... does he have the kind of skills to negate that? I don’t see it... I think Hernandez can keep him on the end of his jab and while he wasn’t a banger, his punch is hard enough to keep Gamboa honest...