There are places that print out rubbery stuff, but I think they're pretty expensive ( you can even get things made up in titanium if you like - if you have very deep pockets
The place I'm getting mine printed at charge by total swept volume - it's 10p per CC of swept volume, so a sun shade would work out to be pretty expensive to make I reckon - 60mm x 60mm x 100mm = 360cc = £36 + vat. Although I can use the empty space to fit other parts in.. so for example, I could probably fit a dozen turrets inside the sun shade tube and effectively get them for free (if that makes sense).
I reckon I could easily do a replacement turret for a Nikko - are they fixed in place with grub screws?.. not sure if the nylon would be strong enough to hold a thread.. I guess it might be - or perhaps use a helicoil..