This tone stack is also used in the Alembic and Acoustic 360 preamps. A slightly modified version was used on Marshall Super Bass and Sunn (non-Coliseum) amps, based on the slightly earlier Bassman design.
I'm starting to think that, maybe the best way to get an Alembic preamp sound is actually the lowly Hartke. And no wonder Jaco went with them, as they share a similar tone stack with his trusty Acoustic 360.And maybe SWR had the Aural Enhancer to simulate such a tone curve while using active EQ?
The interesting thing is that, on Fender's later Bassmen, the "bass" inputs are actually less scooped than the "normal" ones with this tone stack. With Marshall, the Super Lead tone stack is slightly less scooped than the Super Bass one. Maybe Fender was seeking maximum "hearability" from underpowered amps, while Marshall was confident with their power and just slightly adjusted them for a bolder lead tone?