Doesn't his have a Sadowsky preamp (and maybe pickups)? I've been using the pedal version for years on my passive basses. I COULD live without it, but I like just a touch of bass and treble boost. Their pres are boost only BTW, so fully counterclockwise is actually zero as opposed the 12 o'clock being zero.
ANYWAY, that's a cool little factoid about the s/n!
This is the Marcus line -
https://www.sire-usa.com/product-category/bass/A friend of mine has an M series (non-Jazz style). Seems like a good instrument. I haven't actually played it plugged in.