I just realized you're the guy selling the pickup in the classifieds lol.I think so. And that is based on putting another Precision pickup into the Ultra and thinking that I had the same problem with it tone-wise, whereas it was fine in another Precision. It's hard to be conclusive though because my experience was with one Precision Ultra and while a have a Precision Ultra split P, I have never tried putting it in another bass.
If they are weak, I guess adding an active preamp would add some life to it. I have a Bartolini active/passive preamp that would make an interesting combo.