Here is a chance to own a piece of San Francisco history. This is an original Thanksgiving Day column typed by Caen, most likely two-fingered on an old Royal typewriter as was his style even after computers came to newsrooms. Caen wrote a 1,000-word column six days a week for 58 years, longer than anyone in the history of American newspapers. The subject of this wry column - turkeys in general, the "Chief Turkey" in the Bush White House and troops in Saudi Arabia - is especially interesting.