Must be true as I read it on the Internet, here is some more info from
http://forums.fender.com/viewtopic.php?t=7006They note
The dark stripe on the back of the neck, known as the 'skunk stripe', was originally to fill up the hole through which the truss rod was fitted. As the necks were made of one piece maple, including the fingerboard, there was no other way of getting into the neck. The wood itself adds nothing structurally...it just closes the hole.
Fender stopped using a skunk stripe between 1960 and around 65, when they introduced rosewood fingerboards. As the truss rod could now be loaded from under the fingerboard, they abandoned the stripe.
Fender restarted maple finger boards, and reintroduced the skunk stripe in, I think, the late 60s. As the stripe had now become part of the Fender image, they left it in, even on rosewood fingerboard necks.
In the past decade, Fender started producing graphite reinforced bass necks. There is no room in these necks to include the reinforcement AND the skunk stripe, so the stripe goes. If you have a look at the recent American Deluxes, and Standards, you will notice no skunk stripe. You will also notice that even the maple fingerboard necks are two part...neck and separate fingerboard.
If you look at the non graphite reinforced vintage series basses, you'll see they still have skunk stripes.