PEBBLE BEACH, CAReggie Jackson, the legendary power hitter who earned the nickname "Mr. October" for his World Series heroics with the Oakland A's and New York Yankees, is still Mr. October as far as his librarian, Jody Halloway, is concerned. "Regardless of what else he does, Mr. Jackson has always been a classic gentleman," said Halloway, re-shelving the three bestsellers Jackson checked out in his last three consecutive library visits. "There's something about Reggie and this month... He just seems to be that much more remarkable this time of year, from getting the big volumes off the upper shelves to doing cleanup duty in the kids' section." Halloway did acknowledge that Jackson's outspoken nature and penchant for self-promotion has led to a spate of locally infamous flare-ups with Yankee Deli manager Millie Barton.