Why The Engines That Flew On Saturn V Rocket Look Different In Museums

The F-1 engine is the most powerful single chamber rocket engine, and 5 of them were used to power the 1st stage of the Saturn V rocket. However when we see close up video of the engines lifting the rocket they look a lot different from the examples we see in museums. The detailed pipework is covered up by what looks like sheet sheet metal that's been hammered into place. This is insulation designed to protect the engines from heat radiated from their neighbours, and from hot exhaust gasses that get sucked up onto the back of the rocket. If you want to buy a copy of the Saturn V Manual i showed it's available on Amazon here: https://amzn.to/2tUcNcE