There's a few items such as the drive shafts, CV joints and brake rotors that are not painted and will always get some surface rust fairly quick, but the other painted suspension parts are quite typical for areas that salt the roads - quite possible that it was driven by the dealer or driven to the dealer on salted roads and never rinsed off.
In the photo of the brake rotor it looks like a bolt that's not fully tightened - got another photo of that?
It would be very difficult to stand your ground with the dealer on the superficial rust, but would admit, not something I'd like, and many dealerships have similar discounts on vehicles that don't show those signs, and don't believe that's behind the discount you got.