I can tell you where it came from, the end credits of part of the Slimer and the Real Ghostbusters season… with corrected speed.
It’s not the whole intro sequence as it lacks the a chunk of the guitar riff when the Ecto-1 screams out of the Firehouse and the scene changes to Stay Puft and the other ghosts in the original intro.
Speaking of RGB music, does anyone know where I could find the background music from the show? Not like the ones from the soundtrack, but the ones that were background instrumental songs? For instance, in “Ghost Fight At The OK Corral”, when Peter traps the ghosts and blows off the trap, the song that is playing in the background.
Anyone have any leads? Thanks go out in advance to anyone with any information!
Hey Man! 
Thanks for posting that! :o That’s awesome!!!
I’m also interest in the back ground music… The tune that comes to mind is in the Sandman episode. It played after Einstien walked away and Winston was left on his own… I’ll do some searching, it would be nice to have those songs.
None of the instrumental stuff (IE, stuff that isn’t the main theme or features lyrics), has ever been released officially or unofficially.
Looks like Im a few years too late and all the links to it have died. 
This thread has some of the incidental music; I think I have most of what’s here saved someplace.
That would be wonderfull if you still do!
Has any one asked Polydor Records?
All Im really looking for is the theme song all nice and clean e.g. no sound effects in it.