It is my understanding that it is completely false that the founder of BodyWorlds ever used Chinese prisoners or any other bodies attained by unsavoury means. According to Science World's information, all the bodies, past and present, were donated by the person to this specific project before they died. Gunther von Hagens himself was the victim of political discrimination, having been imprisoned for two years in East Germany for political reasons.

There are other exhibits touring that have imitated the plastination techniques and even copied the displays. Some of those may use bodies attained illegally or immorally. I agree with your concerns, and wouldn't have gone to the exhibit myself except for the reassurance that these were donated bodies. I'm considering the donation process myself, in case I die in a way that doesn't allow my organs to be used in transplants.

If you decide to go, I highly recommend spending the extra $5 for the audio tour - it was highly informative.