Dick York, Dick Sargent, Sergeant York... coincidence, I don’t think so.
Here's a little-known fact for ya, Sammy:
Dick Sargent (Darrin # 2) was originally offered the role of Darrin when they were first casting the show. He could not do it, however, due to other acting commitments he had at the time, so the role went to Dick York. When York's deteriorating health prevented him from continuing with the show, they went back to their original choice, Dick Sargent.