Sure, it basically puts the pickup out of polarity with the other one. Famous users of this sort of trick would be folks like Peter Green with his famous LP from the early( when they were blues rock) Fleetwood Mac records. Pretty obvious sound change when both pickups are on.
Also, for a covered pickup like a Gibson PAF, it changes slightly, the focus of the single pickup as it moves the uncovered poles about an inch closer to or further from the bridge, depending on which pickup you flip.
It basically will yield (in the middle pickup position) a somewhat thinner slightly hollowed out mids sound. Actually, to my ears, your 335 already sounds like it has been done to it in some of your clips, which is why i asked about wiring mods that one time.
Another thing to try(but not on a vintage guitar) is to actually loosen the pickup up and remove and flip the magnet inside to reverse its magnetic polarity, while retaining the uncovered pickup pole's positions.
I actually haven't found any of these sounds very useful for what i do, but they sure are different.
