The pickups are exactly the same as the ones of their high-end models. The pre is different though.
To me the old RBs didn't sound like a German W, but in the same time those do maintain some tonal characteristics of their big brothers, and their voice is powerful and articulate.
AFAIK Wicks come with stock Black Label strings, that add a specific zing to the sound. But honestly I hate 'em, way too abrasive for my taste. The good thing is though most strings will sound good on these basses, so switching between brands is not a problem.
So yeah, I'd say it's the bass rather than consumables such as strings - prolly using as many identical components to the German Wicks on RBs help these maintain a certain feel & tone.