+1 on it being a freewheel. I can make out TAIWAN, possibly a Sunrace?
The original Suntour cassettes used a system similar to Uniglide...threaded last cog.
But their freehub body was removed via a 10-12mm hollow bolt from the NDS of the hub shell.
IMO, a superior improvement over the Shimano design, and a clever way to get around their patent. It's easier to manufacture, and yields a stronger rear hub.
This set up is still in use today by Joytech and Formula.