What kind of bass is it? If it's one of the major companies, places like Jeanies & Pickguardian have the 'standard' templates they can use. You do run the risk of having an odd cavity that isn't completely covered or pg holes that don't line up, but if you're not queesy about drilling, you can easily redrill the holes (fill the old ones first with toothpicks and wood glue and let it dry over night though).
Official Fender PBass Club - #734, MIM PBass Club - #124
It's not out of the question that you might have a very minor case of serious brain damage.