Oh, okay. Would it be possible to use a script function like you say to swap the pointers of the palletes to new, black and white ones? We know how to make things black and white on FireRed, but unfortuately, it can't be done on Ruby, which is the rom my friend wants to use.
Edit: I was able to find the pointer that points to the pallets. Let's say that I saved the background pallets in VBA and converted it to grey scale. How could I reinsert it back into the rom and then make the pointer dynamic based upon a flag or such.