Looking at the pics of the shuttle in the display case...
https://pbs.twimg.com/media/CpHYi0jUEAIhqBn.jpg:large
....that doesn't look nearly in scale to the other ships? In the movie, the body of it looked about twice as high as a TIE Fighter's cockpit sphere. Here...looks no bigger than the TIE cockpit. Smaller, even?
I didn't see a comment in the article on it, but... no way that is 1/270...