Gogo's lie- Detective Riddle

Gogo told a story about how he was awarded a medal for ?ravery during World War 1? Why is this a lie?

They didn? know there was going to be a World War 2 at the time, so they wouldn? have said World War 1 They didn? know there was going to be a World War 2 at the time, so they wouldn? have said World War 1