Husky and Lima
Don't know if you saw, but I asked this same question in Part 25:
http://www.talkbass.com/forum/f8/spector-club-part-25-a-849502/index37.html#post12146727
I ran into this when upgrading my NS2A to active EMGs. However, I was careful to note the original wiring and polarity of the stock passive pups before I removed them and it was wired in this "reverse" manner when I got it. I took pictures of the connections on the preamp labelled F PU and R PU which I took to mean front (P pup) and Rear (J pup) and put them in the post for reference.
I considered just swapping them as Lima suggested to make the volume knob layout more logical but then I worried that the preamp might be voiced for a more bass-heavy input from the F PU connection and a more treble-heavy input from the R PU connection so I just left them as I found them.
I suppose its possible that someone switched the original pup wiring before I got the bass.
The only reply to my original post was grendle who confirmed that this "reversed" volume knob layout sounded right to him.
I'd be curious to hear more about your experiences and whether swapping the inputs would affect the tone.