>>63969771
Sure, they copied (or stole) a lot, but they also had their own ideas. I'd say generally that the more "basic" a weapon system was ( a gun, a tube, a tank, etc) , the better & more original they were.

Higher-end platforms (aircraft, ship systems, missiles, sensors, etc) is where they started copying homework when and where they could more. But even then, they'd put their own twist on it.