Hey Woolimwoo,
Welcome to the forum and congrats on your new axe. We like pics in here so post some if you get the chance.
Regarding the fingerboard, anything is possible if you're willing to spend the time and money. But from what I understand about different fingerboard woods (which admittedly isn't much), pau ferro is somewhere between rosewood and ebony in hardness, feel, and probably sound. It may make more difference on a fretless bass, but I'm not sure switching to ebony would make THAT much difference to the sound or feel, especially if it's a fretted instrument. The biggest change would be how it looks so if that's what's bugging you, then yeah.
Other more knowledgeable folks in here may have more to say on the subject.
Jimmy J