ANTIQUES ROADSHOW prepares to break camp in San Antonio, Texas, but first, host Mark L. Walberg and appraiser Bruce Shackelford talk about the colorful history of Mexican cowboys - vaqueros - and the hot market in antique sombreros. At the Henry B. Gonzalez Convention Center, appraisers hog tie some lively treasures, including a collection of memorabilia from a 1957 Buddy Holly and the Crickets concert in Liverpool, England; a quintessential Texas painting of bluebonnets by noted artist Robert Wood; and four unusual Chinese porcelain panels that tell the story of the seasonal rice harvest, valued at $40,000 to $60,000.