Yeah, it's definitely a ball socket. I can't say how it got loose though. Over the years I've done lots of top end work on 103's and I've NEVER seen one just fall out. This reminds me of something I saw in the early 90's. I had a car in the shop with ZERO oil pressure. When I took it apart I found a "woodruff key/keyway" had beat it's way through the oil pump screen and broken the pump, exactly as in brewtoo's case. The car (I think it was a 140) was only two years old, with about 25K on the clock. It never had any kind of engine work done previously, so the piece must've been in there since the engine was built.