I put it back together...for the most part.
 

I was tooling around with my new bass (screwdriver in hand) when I decided to look under the pick guard. I ended up taking the pick up off the pick guard, and had difficulty putting it back together.

I managed to put it back together, but without the springs.

Also there might be a 10% chance that I put the pickups in upside down.:hiding: It won't implode or blow something right?

No explosions.

Don't be tempted to use that screwdriver on anything that runs on 120 vac, if a pickguard is a challenge.

what kind of bass?

if it was a fender-style, with pickups that slip up into plastic covers, you're probably fine; the pickup wires are attached to the bottom plates, so it would have been pretty hard to flip them over (stretching out the wires) then try to jam those wires up against the insides of the covers.

if not, if the pickups were one piece, they would look really weird upside-down.

either way, you need those springs to push the pickups up so that they're close enough to the strings to sound right.