It depends on how resourceful you are… how much you want to spend and how much work you want to put into it. I’ve fabricated them from raw brass material and I’ve modified them out of this premade version that is easy to cut down (for different projects, not Spectors).It would…do you have any sources?
Guyker also makes a Brass roller ball version (on Amazon), I’ve bought one of those too, but I’ve not used it yet.
You could also reach out to Jason at Fret Nation to see if you can order an authentic Spector part.