Question about the plastic tubing inside new FLs

This is such an unusual question, but is there any way you can find these plastic rods separately?

Also, I believe that some of the rods are from a slightly different material (from buying more than one FL, I've compared them) - is there any way of knowing which one you'll get?

The reason I'm asking is I'm quite a fidgety person, and a few years ago after receiving a FL, I realised that rod makes for a perfect thing to spin round my fingers. It's perfectly weighted, doesn't make a rattle noise and the corrugated/ribbed texture makes it easier to hold as well. Unfortunately I've now lost it - just trying to figure out how to replace it and ideally I wouldn't buy a whole new FL to do so, but we'll see...