We don't know that, because it's hard to prove a negative, but I'm also not sure if you chose Cisco on purpose, because a shortcoming by them was leaked: https://www.cnbc.com/2017/03/29/cisco-cyber-defense-flaws-ex...

Supply chain management is a thing. Devices aren't assumed to get from the factory to you without interference and there is a lot of work behind the scenes to make assert they aren't interfered with.