I don't think I've ever seen a handle with removable screws from the factory. Could it be something designed with swappable grips, or just a prototype feature? The grooving itself is Waki-like, but it looks like it's smaller in diameter than Waki handles to me -- possibly a different crash-ax?

Thats interesting, I never thought about those being removable

It will be interesting to see what it is all about