@AshifiliYes, it's golden, since it's Like Proto Gil's
armor, and I assume that this is something that he had for some time, say one of the first treasure he ever found. Just so that you know, the Cataloger has an Archeology major and was part of the research team that is important to the telescope's quest when he stumbled on the Compass, and shortly after the armor set, so Ling should always have known it as such.
Otherwise why would he be called walking gold statue? Like Aria did a while ago IC? He's not that old as well, he actually has around 20 and something years.
Also, about the telescope. He would find out that what made it unique was that its mirror was made from a unique blood red geode that a team of archaeologists, geologists from Sonomachi U found at a recently discovered cave on Guatemala, about 5 years ago. The cave appeared to be a sort of ancient temple/observatory and the geode was used as a focusing mirror. Needless to say, such a discovered rocked the scientific world with almost undeniable proof that the telescope had been created a good 2000 years before the Renaissance.
After a team of physics studied the stone's optical characteristics, they argued that if it was polished and treated with modern measures it could as well become the best land based telescope in the world, which was enough (after a serious argument with the historians) to convince (via money) the Guatemala government to sell them the stone.
Once the telescope was built, however, it was necessary to use a software to correct the strong distortion it had thanks to be able to capture redshift images farm more accurately than any other telescope ever had. In truth, the skies it showed were completely alien to the scientists and they thought that it was likely an image of how the universe was at it's formation, but to put it simply, Ling would be able to make the obvious connection here. The telescope actually can focus on the Crimson Sky's sky. WHat YTC is gonna do with it is left for you to discover.