When I worked for Grant at Apogee in the mid-to-late '80's, he at one point asked me to clean up that model. It was covered with cigarette smoke residue (many at Apogee were heavy smokers back then). It was machined out of aluminum, as the quartz lights in the engines were so hot, and jammed in such a small space, anything else would have melted (the aluminum body acted as a heat sink.) As I recall the miniature, however, it had very little detail and was mostly paint (which made the clean up process rather easy). I am not sure that the image in that article is of the actual item, though my memory could be faulty. Unfortunately, I don't think I ever got any pictures of it during that time, though I have seen BTS photos of the model in various publications over the years.