The problem with a lot of the genuine controllers that have been "refurbished" is that the replacement thumbstick is actually the Gamecube type
If you want genuine the best thing to do is look for a barely used one (eg CiB Japanese). It is still possible to get NOS but they are rarer now and prices tend to get crazy.
The 2 good ones I have I was lucky to get through work (so 20% off marked price) and tested them before buying (not really important as I can return stuff without any issues), but I waited for like 5 damn years to find those
