The reprint of the Style C is easy to spot - look for the small hair or fiber on Leia (see arrow). Many sellers call this a "restrike" poster. The poster is folded, and has no rating. There is a version of this poster that is usually rolled - with a rating .. it is very rare.

An original Style C poster will sell for about $500, depending on the auction, the rolled poster with rating will sell for $1600 or more.