As to this question, I have to tell you several things. Generally speaking, this is an era of globlization, so is economy. At present, a lot of things are being made in one country, but often, some parts of the product are made in other countries or regions in the world. Thus, there are no strict indication that where is product is made in. As you have found on your sunglasses, they are made in China. In fact, Armani do have factories in China, but lots of the product's spare parts are made outside China. If you get them from a big store, they are probably authentic.
When you see the signs like "made in china", it means that the products are processed in china. Although its brand belongs to the foreign company, it is made in the branch processing company in another country. With the economy globalization, many main companies have set their branch companies at the developing countries. So what you see the sunglasses is possible real.