My paint codes are stamped on the driver's door jam sticker just under the bar code strip. I'd guess newer Super Duties have it there as well. Once you have the paint code, finding it at the stealership is easy.
i dont think he has the lower stripe now, he wants the code so he can add it. if you go to the paint shop at your local steal-r-ship, they can tell you the lower paint codes that were options that year.