Bing will look up your board in his old order book and send you a "birth certificate" for it, telling you when it was ordered and who originally ordered it.
Does the logo on your board say it's a David Nuuhiwa Lightweight? When I was a kid, back in 1967 when this model first came out, we called it the "Stepdeck," because of the step down deck leading to the nose. Back then, I never heard anyone call it the Lightweight. Maybe it was just where I lived, but that's what we called it. When I talk with people today who grew up in the South Bay or further south or on the East Coast, they all refer to it as the Lightweight. I haven't heard anyone call it a Stepdeck since I was a kid. Maybe I don't get out enough and there are others who remember hearing it called the Stepdeck, too. I see that you're even spelling it with a capital S. Maybe we were neighbors.
I guess there's a chance we might be talking about two different things. But, it's probably a DN Lightweight. Based on the serial number, your board would be one of the earliest DN Lightweights made. I've been recording most every board we've seen in the last eight years and the earliest DN Lightweight we've encountered was made several weeks after yours. Your board was made in the first week in May 1967. Could be interesting when Bing tells us who it was made for.
The DN Lightweight was the premier high-performance surfboard of 1967, designed for easy turning and greater speed, all in response to the huge shift in surfing from noseriding to a more radical surfing style of deep bottom turns, roundhouse cutbacks, and roller coasters. The 1967 DN Lightweight had the same template as its predecessor, the DN Noserider (the "Concave".... no, just kidding), but it was built much lighter, using a smaller stringer set (3 bands instead of 5 bands) and lighter fiberglass. A lot of work went into shaping this model - I'm not sure how to define the flow of the rails, combined with the changes in the thickness of the board and its rocker, but from a purely aesthetic viewpoint, this is one most beautifully sculpted boards of the period. And, it worked.
If you send me some photos, to email@example.com, I might be able to tell you more about your board.