Barometer of Job Advertising Shows Big Gain: Help-wanted advertising surged in October to the highest level in three years, a further indication that the national job picture is improving after a prolonged slump, the Conference Board reported. But in California and elsewhere in the Pacific region, job ad volume declined in the August-October period. "A full comeback in this region is not likely until late winter or early spring," said Kenneth Goldstein, a labor economist who compiles the Conference Board's employment advertising index. The New York-based business research group's monthly help-wanted index jumped to 105 in October, four points higher than September and 14 points higher than a year earlier. The index, calculated on a 1967 base of 100, measures the volume of employment ads in 51 major newspapers across the country.