DALLAS Back in 1968, when the talent level in Dallas press boxes might have exceeded that on the fields below, a Dallas Times Herald sportswriter named Steve Perkins kept a diary of the Cowboys season with the intent of turning it into a literary masterpiece, if not a quick buck. Unfortunately, Perkins subjects, picked to win it all, finished short of projections, their unseemly exit ranked the most embarrassing in the organization s history. Until last week, that is.