It's definitely there on all the S197 Mustangs, including the GT500's, but it's isolated to the rear axles assembly. Other than the fact that it is not pleasing aesthetically, it's really not a big deal to 99% of people who own the cars. To say the car is a "total rust-bucket" is to imply that the rust issue is prevalent throughout the entire car, which is clearly not the case.
Still, I know some people are going to hang on the fact that it has any rust at all, so I guess a "rust-bucket" it is.
