If it's a current component you can try contacting a Bart distributor like bestbassgear and they may be able to help.
If it's in a bass then you should have some idea of what the scheme is from that. At any rate I'd leave it there and go with a new buffer for the other bass. Makers vary their color schemes and Bart makes/has made so much stuff that it just complicates matters, not to mention custom stuff per other makers specs for their systems. Unlike simple pups there's no way to figure out what electronic components wiring does to my knowledge. You're probably wasting your time trying to adapt it something it wasn't designed for - even though it might work.
I don't buy electronic components that aren't pre-wired, don't have instructions, or the seller doesn't know the wiring scheme for for that reason.