Looks like you get to count, or go down to your Ford Dealer and he can tell you. Bring your VIN if you go to the dealer, they need it for the vehicle ID information. My Service DVD does not have this information.
Because of the mounting bracket for the track bar, I found you can't just drop the control arm from the steering box to count splines. The only way of doing it is to remove the steering box first, and then remove the control arm to count splines.