Had not thought about the rollbar mount, or maybe even between the rool bars, and a Lewis Gun would be appropriate for the period..
I am sure I could get the real deal but a plastic one would draw less flies. There is a local fellow who drives his WW2 jeep that is battle ready and completely authentic around the area with a Browning belt fed air cooled on a pintle mount between the seats. He draws attention, but not as much as another fellow I met that drove a WW2 half track from Montana to a Veterans Day parade in Minnesota with a 57mm anti-tank rifle mounted in the back... he was stopped 6 times by law enforcement who just wanted to look and ask questions. One other compatriate was shooting with us one weekend and he had towed on its own wheels a British 6pdr behind his Chevy Blazer (the large one) from San Francisco 300 miles north to the shooting range, he was stopped once. He had a brake lamp and a trailer license plate hanging on the muzzle brake. All very hilarious that he could do it but he did comment about the lack of tailgators.