Here's Clay's fight with Tristan Yunker at King of the Cage in February 2006. Look at the fight and tell me that's the same Clay Guida competing in the UFC today. No chance you can do it. Specifically, note how much better Guida's rear naked choke defense is as well as his ability to stay calm under pressure when an opponent has back mount.
Secondly, Guida may have the same "advantage" as Huerta. Namely, the UFC keeps giving Huerta match-ups that not only force him to persevere, but teach him how to deal with very different styles and attacks. Well, I don't know if you've been paying attention, but Guida's been getting his fair share of tough fights with opponents who have different styles and attacks. In fact, while Guida hasn't won all of his contests, he's certainly faced a higher level of competition than Huerta.
See for yourself: since joining the UFC, Huerta has faced Jason Dent, John Halverson, Leonard Garcia, Doug Evans, and Alberto Crane. Not bad, but take a look at Guida's line-up: Justin James, Din Thomas, Tyson Griffin, and Marcus Aureilio. If you discount the fight that wasn't against Halverson, Huerta's really only had one more fight in the Octagon. More importantly, not one of Huerta's opponents is as accomplished as Thomas, Griffin or Aureilio. If you factor in that a case can be made for Guida to have won both his fight against Thomas or Griffin, you begin to see the picture a little clearer.
Huerta can beat Guida, no question. But he'll have to rise to the occasion to do so.