Steering rack change over point 430

After lifting the car and tugging on the wheels, there is some play on the steering rack ends and since Ferrari will not sell you rack ends, going aftermarket is the only option. The 430 came with 16mm or 20mm threaded steering racks. The 16mm they shared with the 360. Anybody know when the changeover took place to the 20mm size. My car is a 2005 430. Is it safe to assume I have the 16mm ones given that it was close to when 360s were still produced?