If you have an existing remote: look on the back of the remote. You should see the model number of the remote. It will either begin with a "9" (these are the 390MHz frequency remotes) or it will begin with a "3" (these are the 315MHz frequency remotes). The remotes that originally came with the unit would either be a #973RGD (the older pre-2003 remotes) or a #373RGD (the newer frequency remotes).
If you don't have a remote: Since you don't have a remote to get the model number off of then you'll have to get the information off of the powerhead (the motor unit on the ceiling like the picture above). Remove the light cover and you should see the logic board & where all the wires are attached for the safety sensors and wall station. Now look for the Learn Button. You will either have a Red/Orange Learn Button or a Purple Learn button. If you have a Red/Orange Learn Button then you'll need one of the "9" series of remotes: #971RGD or #973RGD. If you have a Purple Learn Button then you'll need one of the "3" series of remotes: #371RGD or #373RGD.
I hope this helps clear up any confusion so you can determine which remote to get for your Raynor Pilot operator. One last thing, if you want to add a Wireless Keyless Entry to your operator then all you do is use the model number of your remote to determine which keyless will work. So if you determined you need a #973RGD remote then the corresponding Keyless Entry would be a #977LM . If you have a #373RGD remote then the corresponding Keyless Entry would be a #377LM.