The Hartford Insurance Group is going stag, again. After a seven-year absence, it is bringing the live stag back to its television commercials. "A problem with insurance company commercials is that many look alike," said a Hartford spokesman. One way to stand out, the spokesman said, "is having a logo that can come alive." Since 1972, the company has used three different stags in filming 30 commercials. Executives at its advertising agency, McCaffrey & McCall Inc. of New York, say they have one big worry: What happens if the stag's antlers fall off before the shooting ends? So far, it hasn't happened. But there was one close call. The star of Hartford's most recent set of commercials, Lawrence, a European red deer stag, lost his antlers just two days after shooting.