Re: Bridge pickups in the neck??
The reason for flipping is two-fold. 95% of the time, it is so that when you coil cut the pickup, the active coil is in the physical location that you prefer. So if you want the single coil toward the neck, or toward the bridge, you may find that in order to remain in phase with the other pickups you might have to flip it around.
The Fred is a slightly different beast in that it has two different coils. They are not exactly the same. One is overwound vs. the other. So technically, if you flip this pickup around even in humbucking mode, the tone will change a little. It is not as dramatically mismatched as a Steve's Special, Megadrive, or Drop Sonic. But it's enough that I can hear a difference when I flip it in the bridge position. I've never tried flipping it around in the neck position, and it's been awhile since I've heard it as a neck pickup.