Most commercial discs have a registered UPC/EAN number - a unique 12/13 digit number that allows sales of a product to be tracked.
But it isn't essential. Quite a few discs which are not destined for widespread mainstream release don't have them.
The oriental characters are unusual (don't know if they are Chinese or Japanese). Maybe it is a dodgy Chinese pirate copy after all, but on a pressed DVD?
Or maybe it was produced by a small inexperienced publisher, who made an in-house DVDÂ±R master and sent it to a factory in the far east who could manufacture the stamper and do a small production run at a reasonable price.
If the DVD contains The West Wing or 24, I would suspect piracy. But if it is something more unusual from a smaller company, they are probably legitimate.