That's the ones that I have on my Chinese Club ... https://www.hofner.com/guitars-basses/guitar-accessories/guitar-strings/hofner-bass-strings-flat-wound.html
They are different to the Contemporary series. They are, I believe, made by Pyramid. And I have seen a close up pic of McCartney's Hofner and it appeared to have the dark green silks.
https://www.hofner.com/guitars-basses/guitar-accessories/guitar-strings/hofner-bass-strings-nylon.html
These black nylons have bright lime green silks.
I struggled to get the E string through the tuner and so stuck to the ordinary flatwounds above. However, here in Brighton, I have spoken to a guy busking on a Chinese Hofner with Hofner black nylons, so it can be done and he sounded great.