I don't know about the factory, but I know at my Walmart, the Buck lookalikes are a different brand than the ones we've been talking about. Doesn't necessarily mean it's from a different factory, but based on how you describe the knife(uneven grind, splotchy paint, uneven pin) I'd say it's probably either a diff factory or at least made to diff standards.
All of the $3.87 knives are made at the same factory.