Most of the exterior wear was caused by exposure to Florida's weather (sun, humidity, temperature variation etc). It's the flume and nearby concrete getting backsplash that is affected by the treated water. Unless that's what you meant.
I don't know if the ride has some sort of reputation for leaking these days. It did have some leaking problems on the final lift for a couple of years prior to 2013. But the outer layers of thematic concrete likely provided SOME form of protection to a lot of the underlying structural steel and concrete. As far as i'm aware, a lot of the mountain is also hollow and accessible to work crews so they can view a large portion of the structural support from behind without needing to tear anything out. I doubt they're going that deep into the foundation either. So if there are any issues with that, they might not even find it.
I'm not trying to say your concerns are unfounded. But I also think they have already been able to do a lot of important preliminary structural inspections to know what they're getting into. Particularly during that major 2013 rehab.