The original "radial" is manufactured only by "uniloc corporation". A few cue makers now offer a very similar pin, with only a tiny bit of difference from the "uniloc radial", that they manufacture themselves, or buy from a supplier other than Uniloc.
The two pins are not interchangeable.
Some people call this second pin 3/8 x 8 radial, or 3/8 x 8 ball, and perhaps other names I'm not aware of.
In the US, I believe Mike Webb and Rat Cues (both forum members here) will be able to make you a shaft with these threads without any issues.
Finally, since you bought the cue from the cue maker himself, and he seems to respond to questions on his sale thread, the question you want to ask him is if his pin is compatible with "uniloc radial".