Sure it would work, why wouldn't it? That is, unless you grab one of the very early pickups (up to 77') that have the longer pole pieces, those won't fit in the cavity.
I've turned one of my previous 3 band Stingrays into a "2 band", kind of, sort of. I've replaced the preamp with the John East MM 3 band preamp (it's based on a 2 band preamp, with the additional mid/sweep control) so I could fit all 4 knobs. I worked nice with the Nordstrand MM4.2 pickup, but ultimately, with all of my experimentation with preamps and pickups, my favorites were stock Stingray pup+preamp.
My suggestion is to either get a 2 band Stingray (sell the 3 bander if you don't like it), or if you must experiment, try swapping out the preamp first, no need to replace the pickup. If you can, find the original 2 band preamp, or one of the better aftermarket ones that are replicas of the Stingray 2 band. That alone will give you the 2 bander flavor, and is the cheapest route, and you can easily put the original preamp back in.
