The LEM had a single oxygen supply shared by both astronauts.
My dad built the valves designed to shut off the oxygen to any astronaut unfortunate enough to get a hole in his suit, quickly killing him, but saving the other astronaut from suffocating along with him.
Why would they bother to fake that detail if they didn't actually go?
Each contractor and sub contractor did their job to the best of their ability—and got paid well for it.
But—at the end of the day we had to fake it because we could not make it—no contractor’s fault, just the political goals exceeded the technological reality so the politicians decided to go the false glory route.
Take a look at the command and lunar module computers—there was no way they could possibly work—and NASA knew it. That meant navigation became impossible once the communications delay from Earth kicked in.... (four seconds each way to the Moon) which in turn would mean certain death for the astronauts:
https://www.aulis.com/pascal.htm
https://www.aulis.com/pascal2.htm