These are CNC turned in technical polymer, thread made per NOS green cap, and got passed throw a surface finish. These are design to be press-fitted as per genuines.
I heard from a buyer that fit a green cap from minispares with no issues. I have fitted a green cap replica (don't know source) also without major issues. But these, anyway, are design to fit genuines green caps

I hope that all genuine stalks can have a second Life!
Price: 22gbp + postage! [just black end itself, no green caps]
I am in Portugal, happy to ship.
- 3rd batch now available!
Nuno Moita