The PIC system software has multiple parts.
There is two processors in the pic. The Master processor controls the access to the motor, transmitter, sensors, etc.
That program is has a suffix ending in .bin and it need to be loaded first
The second program controls the second processor and all of the use control functions. On the VEX site there is a pretty cool program that does this for you. That program ends in .hex. You should try to find and load it, it will give you the best instant driving checks.
So for basic functions you need the .bin and the ,hex program.
Lets move to RobotC. Robot C uses the .bin program since that talks to the motors/sensors/etc.
It has it’s own program for the user processor that it downloads. It also has a .hex ending. This special RobotC program talks to the RobotC program that you are writing and is how it gets downloaded and run.
I’d get the VEX software that works with the 0.5 hardware and download the basic .bin (master CPU) and .hex (user driver) control. I’d make sure that all of that works.
Then I’d get the RoborC stuf and download the ,bin file for that version, and the .hex file for the basic loader and then download a sample program.
All of this is one way downloads, there is no way to pull back the code that was downloaded.