I recently picked up a '75 Jazz (4 bolt) with a maple fretboard. It has quite a chunckier neck than I have seen on a Fender Jazz Bass. I read somewhere that this is known as a "U" shaped jazz neck. Is that correct? If so, what years was this neck in production? One other question, I thought that by 1975 all Jazz basses were 3 bolts. Is this just a transition bass? I could not read the neck date but it did have a "Herb G." stamp on it.