DrAlex

This is only partially true because Discovery received some visible modifications between those missions. Between STS-31 and STS-82 Discovery got the new external airlock to dock with space stations, which is of course missing in the cargo bay in the set. If you look at the picture in the Wikipedia article of STS-82, the external airlock is the circularly shaped object in the lower part of the picture. And between STS-82 and STS-103 Discovery got the new NASA logo on the left wing and the US flag moved from the left wing to the right wing, which is why the outer appearance also doesn't fit anymore at this point.