Yeah, I'm aware of those - but they're intended for the pre-2018 Stingray.
No, they are intended to be used wherever you want to use them. They're not designed as a drop in replacement, they're not the crescent shaped preamp like the original Stingray ones are.
Since the pickup was modified, and the preamp re-voiced for the Stingray Special, I've no idea if those particular 3rd party preamps would be a good match for the Special pickup.
Hard to say, it might not yield the results you like. I had an original 2 band ray preamp paired with Nordstrand MM4.2. I didn't the like the way the low end was reacting when boosting bass. Nordy was more focused on the low mids, so if I cranked both knobs, I'd just get a tinny tone without that signature Stingray low end. Returning the stock pickup cured this. Pairing the Nordy with a John East preamp though gave me a much better result as I had control over the mids frequency, and was able to boost low mids when I wanted to.
When I asked one of the Ball family if there was a setting on the Special preamp, that matched a particular setting on the old 2 band preamp (as there is on the old 3 band), they said there is no corresponding setting, nor was there intended to be.
That doesn't necessarily preclude the old 2 band working in a predictable way with the new pickup, but I got the impression that it's a symbiotic system - an old pickup with the Special preamp might just as easily sound great / terrible (I'm assuming they were changed as a complete package for a reason).
Do you know of any 2 band preamps that are specifically designed for the Special?
I'm just curious. I'm wouldn't be interested in making that modification myself.
There are no after market preamps that are designed to fit a certain bass. There are only designs that are either based on existing designs, be it vintage or modern, or are new designs, not based on something.
@Tuna Can Dan swapped the neodymium pickup on his Special for an alnico one (Aguilar AG4M), you might wanna ask him about it.
And yes, there's a certain symbiotic system with the preamp and the pickup(s). I've tried several combinations with old Stingrays and the stock ones did it best for me - for both 2 banders and older 3 banders.
As for a 2 band sounding preamp, John East 3 band preamp does this and fits 3 band Stingrays, so it should fit a Special too. That said, it's a slippery slope, and you'd be better off grabbing an older 2 bander for that tone, rather than modding a Special.