The pickups are identical internally. The engraved ones are slightly farther away from the surface so the coil doesn't pop through, but they are as close as possible. The ones with the gold script in the ABS plastic shell are closer to the surface and always the same since they are just resting on the bottom when casting as opposed to being suspended over the mold like the block letter engraved type.
I would be surprised if anyone could hear the difference.