I had my wife's 09 done at the Ford Dealer in Heflin Alabama in June. They had parts in stock. My 07 GT500 lives in California. Called the dealer in Santa Monica the following week, and they had no parts, couldn't get parts, and had no idea when they would have parts available.
A call to Ford shed a little light on this confusing topic. It was explained to me that parts were being distributed in 3 phases, with high humidity locations given first priority. Then snowbelt, then everyone else. So, Arizona and California type climates will be the last to be serviced. Leads me to believe that corrosion may accelerate the rate of failure in their opinion.
I'll be driving the GT500 back to Alabama next month, and WILL be having it serviced!