They may not be able to replicate the materials used to build the aircraft. However as the article explains, they have all of China's resources at hand and Chin

They may not be able to replicate the materials used to build the aircraft. However as the article explains, they have all of China's resources at hand and China can surely build a decent turbo fan engine and the electronics are the easiest part to reverse engineer. The basic components are likely to have some production in China and all that corporate/DoD espionage gives them a leg up in mirroring whatever we design. Material science requires far more technical and scientific expertise along with significant investment in production and the coatings and alloys are key to proper stealth but just having a capable drone will be enough to give Iran powerful reconnaissance capability even if we have the advantage in detecting their design.