On the sim it should have mode #1 or #2 and mode #2 is the one most often found, throttle and rudder on the left, aileron and elevator on the right, but it's A choice thing. And like Joe mentioned, not all RXs are the same, what chuck C mentioned is the norm for Futaba and High Tec.
For the real deal do what Chuck W said, A P-51 is A bit different then A Cub of any type. If you have A local club contact them, they may have A trainer plane with A buddy box and an instructor so you can get some lessons then make your choice. No reason to spend money on something you may not want.