I think that's something very heavily modified or even mocked-up. Those leading struts look like they came from a post-WWII Pitts, not WWI or 1920s. The head visible is so far back that their arms won't reach the gun -- which was always a requirement to clear the frequent jams. So is/was this a two-seater with a gunner ahead of the pilot? I can't see any trace of a prop-disc, or even the bolt circle to attach the prop to the crankshaft, which is how a mock-up to be filmed in front of a background would be. That roundel could be British or French but there's a lot of white there for a combat aircraft.
Is the movie any good, is it worth searching out on DVD?