Even though it looks like a minor mishap, it is quite common for later hydraulic cammed engines to also have this happen occassionally. If you are planning to reuse the lifters, just make sure the bottoms of the lifters aren't showing signs of excessive wear, and you should be able to just reinstall the clips into the lifter body.
Is there any way to if this is what happened? Am I right in assuming if this was the case, there would be a gap between the lifter and the cam?
