I doubt it and I know of no reason that it needs to be stored. The key has to be presented either to encrypt or to decrypt a passcard and it can be cached by the program for some period if it is so configured.
Yes, the encryption key is a Master Password for the program.
Maybe try it out - it's free to download and to use for up to 10 passcards.
I now have over 1100 passcards and am highly dependent on it and unable to consider using any browsers that RoboForm does not yet support (eg, Opera or Google Chrome).
Tony