Regarding the mysterious center clip - this is the original Nikkor reel. What you see is not a clip, but a blocker that forces you to enter the end of the film in the right slot of 4 available. If you do this, it will load smoothly and easily onto the reel without the complication of clips.
There are many folks out there who are on constant vigil for this kind of reel (they are hard to come by these days), and possibly why Mr. Simpson jumped on this. Good for him.