A lot of factories pump out "replicas" when they aren't shipping to GM's factories (or any OEM). Tooling is not making money if it's not running. Also it's expensive, so not just every Joe-Schmoe-Co. is gonna spin up something that won't sell. Of course this changes over time, OEM tooling gets sold off, popular designs get copied, etc.
If it's a newer design, probably same factory as OEM, just de-branded. If it's been around, it might be OEM tooling sold off, or (if it's popular) it might actually be a replica, new tooling, non-OEM factory, with unknown quality control (unless they have a reputation they want to keep).
Of course, with wheels, a true failure (outside finish flaking) would be a massive lawsuit, and end most any janky company, so I would not be too scared of any wheel that has an actual company attached to it.
My pennies,
-bZj