GET THEM WHILE THEY LAST: Dying for a pair of Levi’s Brain Dead jeans? Well, J. Crew men’s stores in lower Manhattan recently snapped up the last of Levi’s Vintage Clothing stock and are selling the jeans (and one style of sack coat) exclusively at its new shop at 484 Broadway as well as the Liquor Store unit on West Broadway. The selection — which is limited edition and re-created using the original techniques from 1873 — include the Dead Stock from 1967, the Brain Dead from 1947 and the Barren Land from 1937. They retail from $195 to $395. The Sack Coat is from the Twenties and sells for $298. Frank Muytjens, J. Crew’s vice president of men’s design, said the iconic pieces “replicate the fabric and wash” of the originals and are even “woven on the original looms.” As of Thursday, there were between 40 and 110 pieces of each style, Muytjens said, “and when they’re gone, they’re gone.”