It might be deceiving, but to me it looks like a 3mm pivot pin, which is a bit thin for a knife that size. It might even be brass.
Do you think that the brass bar that is externally visible IS the pivot, or do you think that there is something else lurking underneath in the works that we cannot see?
Surely, from a makers viewpoint, a seemingly weak pivot set up, on what is clearly a hard use folder, would be a bit of a gaffe?
"This is my rifle.There are many like it, but this one is mine"
Sharpen it like you love it, use it like you hate it.