I lived in Taiwan before & their locally released VCDs & DVDs do have Chinese characters on them. I don't know about Taiwan BDs as there were no BDs yet at that time.
As far as I know, Taiwan is now very strict with movie piracy, so BDs bought in legitimate shops should be original.
It actually looks original, the packaging and all. I just can't validate it since it has Chinese characters.
The bd copies from China that are being passed by Llamas dealers are of the 25GB variety. Siguro if the bds you're getting are of the 50GB kind and priced similarly with authentic bds then its probably more or less legitimate.
How would I know if it's 50GB or 25GB?