You can tell a lot about what they're making based on its proximity to other resources, the shape of the buildings, the schedule of supply deliveries, etc. Intelligence analysts are a crafty bunch.
Yes but - shipping schedules, raw materials, invoices and hirings will tell you a lot more about that than high resolution sat photos of a building in an office park in a city center
1960s - we have photographed Soviet SAM sites around Moscow. We know where to avoid to send bombers in.
2010 - we have photographed a semiconductor fab in china. We don't know what they are making but we can tell where the fab is to an inch.