first, that's NOT an authentic uni-loc joint pin. It is a knockoff. Secondly, you should put a ruler next to threads and maybe we can tell the TPI by the picture.
If you download the free Thread Pitch app, you simply compare your pin to image in the app (not my screenshot) and you'll know. Comes in handy when you left your thread gauge at home and someone asks if his pin is 10 or 11 TPI.
That's the over seas version.
It fits the uni loc very well but the bottom is close to 3/8" in size. I haven't tried to use or find out the thread size yet. because its heavy. To dam heavy.
Couple of Customers tried to supply thier own for me to install. I put the real deal instead.